United States congressional apportionment - wikipedia United States congressional apportionment Allocation of congressional districts in the House of Representatives after the 2010 census. United States congressional apportionment is the process by which seats in the United States House of Representatives are distributed among the 50 states according to the most recent constitutionally mandated decennial census. Each state is apportioned a number of seats which approximately corresponds to its share of the aggregate population of the 50 states. However, every state is constitutionally guaranteed at least one seat. Because the size of a state 's total congressional delegation determines the size of its representation in the U.S. Electoral College, congressional apportionment also affects the U.S. presidential election process as well. Allocation of congressional districts after the 2000 census. The 435 seats of the House grouped by state ( post-2010 Census reapportionment ). Contents 1 Reapportionment 2 Constitutional texts 3 House size 3.1 Controversy and history 3.1. 1 Clemons v. Department of Commerce 3.2 Proposed expansion 4 Apportionment methods 4.1 The method of equal proportions 5 Past apportionments 6 Changes following the 2010 census 7 Past increases 7.1 1789 -- 1800 7.2 1801 -- 1820 7.3 1821 -- 1840 7.4 1841 -- 1853 7.5 1854 -- 1880 7.6 1881 -- 1900 7.7 1901 -- present 8 See also 9 Notes 10 References 11 Further reading 12 External links Reapportionment This article is part of a series on the United States House of Representatives History of the United States House of Representatives Members Current members ( by seniority by age non-voting ) Former members Hill committees ( DCCC NRCC ) Congressional districts Speaker of the United States House of Representatives ( list ) Party leaders Democratic Caucus Republican Conference Politics and procedure Committee of the Whole Closed session ( list ) Saxbe fix Committees ( list ) Procedures Origination Clause Quorum call Unanimous consent Salaries Apportionment ( Huntington -- Hill method ) Redistricting Gerrymandering Articles of impeachment Self - executing rule Rules suspension General ticket Plural district Places United States Capitol House office buildings ( Cannon Ford Longworth Rayburn ) The number of voting seats in the House of Representatives is currently set to 435, and has been since 1913, excluding a temporary increase to 437 after the admissions of Alaska and Hawaii. Though the actual reapportionment will normally occur in respect of a decennial census, the law that governs the total number of representatives and the method of apportionment to be carried into force at that time can be created prior to the census. The decennial apportionment also determines the size of each state 's representation in the U.S. Electoral College. Under Article II, Section 1, Clause 2 of the U.S. Constitution, any state 's number of electors equals the size of its total congressional delegation ( i.e., House seat ( s ) plus Senate seats ). Federal law requires the Clerk of the House of Representatives to notify each state government of its entitled number of seats no later than January 25 of the year immediately following the census. After seats have been reapportioned, each state determines the boundaries of congressional districts -- geographical areas within the state of approximately equal population -- in a process called redistricting. Any citizen of the State can challenge the constitutionality of the redistricting in their US district court. Because the deadline for the House Clerk to report the results does not occur until the following January, and the states need sufficient time to perform the redistricting, the decennial census does not affect the elections that are held during that same year. For example, the electoral college apportionment during 2000 presidential election was still based on the 1990 census results. Likewise, the congressional districts and the electoral college during the 2020 general elections will still be based on the 2010 census. Constitutional texts The subject of Congressional apportionment is addressed twice in the U.S. Constitution. Initially, the apportionment of House seats was guided by two sentences in Article I, Section 2, clause 3 : Representatives and direct Taxes shall be apportioned among the several States which may be included within this Union, according to their respective Numbers, which shall be determined by adding to the whole Number of free Persons, including those bound to Service for a Term of Years, and excluding Indians not taxed, three fifths of all other Persons. The Number of Representatives shall not exceed one for every thirty Thousand, but each State shall have at least one Representative ;... Following the end of the Civil War, the first of those provisions was superseded by Section 2 of the Fourteenth Amendment : Representatives shall be apportioned among the several States according to their respective numbers, counting the whole number of persons in each State, excluding Indians not taxed. But when the right to vote at any election for the choice of electors for President and Vice-President of the United States, Representatives in Congress, the Executive and Judicial officers of a State, or the members of the Legislature thereof, is denied to any of the male inhabitants of such State, being twenty - one years of age, and citizens of the United States, or in any way abridged, except for participation in rebellion, or other crime, the basis of representation therein shall be reduced in the proportion which the number of such male citizens shall bear to the whole number of male citizens twenty - one years of age in such State. House size Ratio of representation in the House, 1789 -- 1913 Years Source Constituents per Rep. 1789 U.S. Const. ≥ 30,000 1793 -- 1803 1790 Census 34,436 1803 -- 1813 1800 Census 34,609 1813 -- 1823 1810 Census 36,377 1823 -- 1833 1820 Census 42,124 1833 -- 1843 1830 Census 49,712 1843 -- 1853 1840 Census 71,338 1853 -- 1863 1850 Census 93,020 1863 -- 1873 1860 Census 122,614 1873 -- 1883 1870 Census 130,533 1883 -- 1893 1880 Census 151,912 1893 -- 1903 1890 Census 173,901 1903 -- 1913 1900 Census 193,167 1913 -- 1923 1910 Census 210,583 The U.S. population has increased more rapidly than the membership of the House of Representatives. The size of the U.S. House of Representatives refers to total number of congressional districts ( or seats ) into which the land area of the United States proper has been divided. The number of voting representatives is currently set at 435. There are an additional five delegates to the House of Representatives. They represent the District of Columbia and the territories of American Samoa, Guam, the Northern Mariana Islands, which first elected a representative in 2008, and the U.S. Virgin Islands. Puerto Rico also elects a resident commissioner every four years. Controversy and History Since 1789, when the Federal Government began operating under the Constitution, the number of citizens per congressional district has risen from an average of 33,000 in 1790 to almost 700,000 as of 2008. Prior to the 20th century, the number of representatives increased every decade as more states joined the union, and the population increased. In 1911, Public Law 62 - 5 raised the membership of the U.S. House to 433 with a provision to add one permanent seat each upon the admissions of Arizona and New Mexico as states. As provided, membership increased to 435 in 1912. As of May 2016, there is approximately one representative for every 720,000 people in the state. In 1921, Congress failed to reapportion the House membership as required by the United States Constitution. This failure to reapportion may have been politically motivated, as the newly elected Republican majority may have feared the effect such a reapportionment would have on their future electoral prospects. Then in 1929 Congress ( Republican control of both houses of congress and the presidency ) passed the Reapportionment Act of 1929 which capped the size of the House at 435 ( the then current number ). This cap has remained unchanged for more than eight decades. Three states -- Wyoming, Vermont, and North Dakota -- have populations smaller than the average for a single district. The `` ideal '' number of members has been a contentious issue since the country 's founding. George Washington agreed that the original representation proposed during the Constitutional Convention ( one representative for every 40,000 ) was inadequate and supported an alteration to reduce that number to 30,000. This was the only time that Washington pronounced an opinion on any of the actual issues debated during the entire convention. In Federalist No. 55, James Madison argued that the size of the House of Representatives has to balance the ability of the body to legislate with the need for legislators to have a relationship close enough to the people to understand their local circumstances, that such representatives ' social class be low enough to sympathize with the feelings of the mass of the people, and that their power be diluted enough to limit their abuse of the public trust and interests. ``... first, that so small a number of representatives will be an unsafe depositary of the public interests ; secondly, that they will not possess a proper knowledge of the local circumstances of their numerous constituents ; thirdly, that they will be taken from that class of citizens which will sympathize least with the feelings of the mass of the people, and be most likely to aim at a permanent elevation of the few on the depression of the many ;... '' Madison also addressed Anti-Federalist claims that the representation would be inadequate, arguing that the major inadequacies are of minimal inconvenience since these will be cured rather quickly by virtue of decennial reapportionment. He noted, however, `` I take for granted here what I shall, in answering the fourth objection, hereinafter show, that the number of representatives will be augmented from time to time in the manner provided by the Constitution. On a contrary supposition, I should admit the objection to have very great weight indeed. '' Madison argued against the assumption that more is better : `` Sixty or seventy men may be more properly trusted with a given degree of power than six or seven. But it does not follow that six or seven hundred would be proportionally a better depositary. And if we carry on the supposition to six or seven thousand, the whole reasoning ought to be reversed... In all very numerous assemblies, of whatever character composed, passion never fails to wrest the scepter from reason. '' Clemons v. Department of Commerce Main article : Clemons v. Department of Commerce A 2009 lawsuit, Clemons v. Department of Commerce, sought a court order for Congress to increase the size of the House 's voting membership and then reapportion the seats in accordance with the population figures of the 2010 Census. The intent of the plaintiff was to rectify the disparity of congressional district population sizes among the states that result from the present method of apportionment. Upon reaching the U.S. Supreme Court in December 2010, the holdings of the lower district and appellate courts were vacated and the case remanded to the U.S. District Court from which the case originated with instructions that the district court dismiss the case for lack of jurisdiction. Proposed expansion See also : List of U.S. states by population The first proposed amendment to the Constitution within the Bill of Rights attempted to set a pattern for growth of the House along with the population, but has not been ratified. Article the first... After the first enumeration required by the first article of the Constitution, there shall be one Representative for every thirty thousand, until the number shall amount to one hundred, after which the proportion shall be so regulated by Congress, that there shall be not less than one hundred Representatives, nor less than one Representative for every forty thousand persons, until the number of Representatives shall amount to two hundred ; after which the proportion shall be so regulated by Congress, that there shall not be less than two hundred Representatives, nor more than one Representative for every fifty thousand persons. The proposed Wyoming Rule calls for expanding the House until the standard Representative - to - population ratio equals that of the smallest entitled unit ( currently the state of Wyoming ). This proposal is primarily designed to address the fact that some House districts are currently nearly twice the size of others ; for instance, there are just over 1 million residents in Montana 's single district, compared to about 570,000 in Wyoming 's. Although a larger House size will generally result in the smallest and largest districts being proportionally closer in size, this is not always the case. Therefore, in some cases, the Wyoming Rule may actually result in an increase in the ratio of the sizes of the largest and smallest districts. For instance, after the 1990 Census and with a House size of 435, the largest district ( Montana 's at - large district ) had 799,065 residents, 76 % larger than the smallest district ( Wyoming 's at - large district with 453,588 residents ). The Wyoming Rule would have given a House size of 547 in 1990. Using that size, the largest district ( North Dakota 's at - large district ) would have had 638,800 residents, 92 % larger than the smallest districts ( Delaware 's two districts at approximately 333,084 residents each ), which is larger than the 76 % figure mentioned above. On May 21, 2001, Rep. Alcee Hastings sent a dear colleague letter pointing out that U.S. expansion of its legislature had not kept pace with other countries. In 2007, during the 110th Congress, Representative Tom Davis introduced a bill in the House of Representatives that would add two seats to the House, one for Utah and one for the District of Columbia. It was passed by the House, but was tripped up by procedural hurdles in Senate and withdrawn from consideration. An identical bill was reintroduced during the 111th Congress. In February 2009 the Senate adopted the measure 61 - 37. In April 2010, however, House leaders decided to shelve the proposal. Apportionment methods Apart from the requirement that the number of delegates for each state is at least one, a state 's number of representatives is in principle proportional to population, thus assuring reasonably consistent representation to the people regardless of the state boundaries and populations. No method of calculating a fair distribution of voting power across the various states was known until recently and five distinct apportionment methods have been used since the adoption of the Constitution, none of them producing fully proportional distribution of power among the states. The current method, known as the method of equal proportions, has been used since the 1940 Census. The Vinton or Hamilton method, used from 1850 to 1900, was susceptible to what is known as the apportionment paradox or Alabama paradox. The method of equal proportions Further information : Huntington -- Hill method The apportionment methodology currently used is the method of equal proportions, so called because it guarantees that no additional transfer of a seat ( from one state to another ) will reduce the ratio between the numbers of persons per representative in any two states. The method of equal proportions minimizes the percentage differences in the populations of the congressional districts. In this method, as a first step, each of the 50 states is given its one guaranteed seat in the House of Representatives, leaving 385 seats to assign. The remaining seats are allocated one at a time, to the state with the highest priority number. Thus, the 51st seat would go to the most populous state ( currently California ). The priority number is determined by a formula that is mathematically computed to be the ratio of the state population to the geometric mean of the number of seats it currently holds in the assignment process, n ( initially 1 ), and the number of seats it would hold if the seat were assigned to it, n + 1. The formula for determining the priority of a state to be apportioned the next available seat defined by the method of equal proportions is A n = P n ( n + 1 ) ( displaystyle A_ ( n ) = ( \frac ( P ) ( sqrt ( n ( n + 1 ) ) ) ) ) where P is the population of the state, and n is the number of seats it currently holds before the possible allocation of the next seat. An equivalent, recursive definition is A n + 1 = n n + 2 A n ( displaystyle A_ ( n + 1 ) = ( sqrt ( \frac ( n ) ( n + 2 ) ) ) A_ ( n ) ) where n is still the number of seats the state has before allocation of the next, and for n = 1, the initial A is explicitly defined as A 1 = P 2 ( displaystyle A_ ( 1 ) = ( \frac ( P ) ( sqrt ( 2 ) ) ) ) Consider the reapportionment following the 2010 U.S. Census : beginning with all states initially being allocated one seat, the largest value of A corresponds to the largest state, California, which is allocated seat 51. After being allocated its 2nd seat, its priority value decreases to its A value, which is reordered to a position back in line. The 52nd seat goes to Texas, the 2nd largest state, because its A priority value is larger than the A of any other state. However, the 53rd seat goes back to California because its A priority value is larger than the A of any other state. The 54th seat goes to New York because its A priority value is larger than the A of any other state at this point. This process continues until all remaining seats are assigned. Each time a state is assigned a seat, n is incremented by 1, causing its priority value to be reduced and reordered among the states, whereupon another state normally rises to the top of the list. The Census 2010 Ranking of Priority Values shows the order in which seats 51 -- 435 were apportioned after the 2010 Census, with additional listings for the next five priorities. Minnesota was allocated the final ( 435th ) seat. North Carolina missed its 14th seat by 15,754 residents as the 436th seat to be allocated ; ten years earlier it had gained its 13th seat as the 435th seat to be allocated based on the 2000 census. Past apportionments Note : The first apportionment was established by the Constitution based on population estimates made by the Philadelphia Convention, and was not based on any census or enumeration. Statehood order Census Const. 1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th 12th 13th 15th 16th 17th 18th 19th 20th 21st 22nd 23rd Year 1789 1790 1800 1810 1820 1830 1840 1850 1860 1870 1880 1890 1900 1910 1930 1940 1950 1960 1970 1980 2000 Effected 1789 1793 1803 1813 1823 1833 1843 1853 1863 1873 1883 1893 1903 1913 1933 1943 1953 1963 1973 2003 2013 Size 65 105 142 182 213 240 223 234 241 292 325 356 386 435 435 435 435 435 435 435 435 435 435 22 AL -- -- -- -- 5 7 7 6 8 8 9 9 10 9 9 9 8 7 7 7 7 7 49 AK -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 48 AZ -- -- -- -- -- -- -- -- -- -- -- -- -- 5 6 8 9 25 AR -- -- -- -- -- -- 5 6 7 7 7 7 6 31 CA -- -- -- -- -- -- -- 6 7 8 11 20 23 30 38 43 45 52 53 53 38 CO -- -- -- -- -- -- -- -- -- -- 5 6 6 7 7 5 CT 5 7 7 7 6 6 5 5 6 6 6 6 6 6 6 5 5 DE 27 FL -- -- -- -- -- -- -- 5 6 8 12 15 19 23 25 27 GA 6 7 9 8 8 7 9 10 11 11 12 10 10 10 10 10 10 11 13 14 50 HI -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 43 ID -- -- -- -- -- -- -- -- -- -- -- 21 IL -- -- -- -- 7 9 14 19 20 22 25 27 27 26 25 24 24 22 20 19 18 19 IN -- -- -- -- 7 10 11 11 13 13 13 13 13 12 11 11 11 11 10 10 9 9 29 IA -- -- -- -- -- -- -- 6 9 11 11 11 11 9 8 8 7 6 6 5 5 34 KS -- -- -- -- -- -- -- -- 7 8 8 8 7 6 6 5 5 5 15 KY -- 6 10 12 13 10 10 9 10 11 11 11 11 9 9 8 7 7 7 6 6 6 18 LA -- -- -- 5 6 6 6 7 8 8 8 8 8 8 8 7 7 6 23 ME -- -- -- -- 7 8 7 6 5 5 7 MD 6 8 9 9 9 8 6 6 5 6 6 6 6 6 6 6 7 8 8 8 8 8 8 6 MA 8 14 17 20 13 12 10 11 10 11 12 13 14 16 15 14 14 12 12 11 10 10 9 26 MI -- -- -- -- -- -- 6 9 11 12 12 13 17 17 18 19 19 18 16 15 14 32 MN -- -- -- -- -- -- -- -- 5 7 9 10 9 9 9 8 8 8 8 8 8 20 MS -- -- -- -- 5 5 6 7 7 8 8 7 7 6 5 5 5 5 24 MO -- -- -- -- 5 7 9 13 14 15 16 16 13 13 11 10 10 9 9 9 8 41 MT -- -- -- -- -- -- -- -- -- -- -- 37 NE -- -- -- -- -- -- -- -- -- 6 6 6 5 36 NV -- -- -- -- -- -- -- -- -- 9 NH 5 6 6 5 NJ 5 6 6 6 6 5 5 5 7 7 8 10 12 14 14 14 15 15 14 13 13 12 47 NM -- -- -- -- -- -- -- -- -- -- -- -- -- 11 NY 6 10 17 27 34 40 34 33 31 33 34 34 37 43 45 45 43 41 39 34 31 29 27 12 NC 5 10 12 13 13 13 9 8 7 8 9 9 10 10 11 12 12 11 11 11 12 13 13 39 ND -- -- -- -- -- -- -- -- -- -- -- 17 OH -- -- 6 14 19 21 21 19 20 21 21 21 22 24 23 23 24 23 21 19 18 16 46 OK -- -- -- -- -- -- -- -- -- -- -- -- -- 8 9 8 6 6 6 6 6 5 5 33 OR -- -- -- -- -- -- -- -- 5 5 5 5 PA 8 13 18 23 26 28 24 25 24 27 28 30 32 36 34 33 30 27 25 23 21 19 18 13 RI 8 SC 5 6 8 9 9 9 7 6 5 7 7 7 7 6 6 6 6 6 6 6 6 7 40 SD -- -- -- -- -- -- -- -- -- -- -- 16 TN -- -- 6 9 13 11 10 8 10 10 10 10 10 9 10 9 9 8 9 9 9 9 28 TX -- -- -- -- -- -- -- 6 11 13 16 18 21 21 22 23 24 27 30 32 36 45 UT -- -- -- -- -- -- -- -- -- -- -- -- 14 VT -- 6 5 5 10 VA 10 19 22 23 22 21 15 13 11 9 10 10 10 10 9 9 10 10 10 10 11 11 11 42 WA -- -- -- -- -- -- -- -- -- -- -- 5 6 6 7 7 7 8 9 9 10 35 WV -- -- -- -- -- -- -- -- -- 5 6 6 6 6 5 30 WI -- -- -- -- -- -- -- 6 8 9 10 11 11 10 10 10 10 9 9 9 8 8 44 WY -- -- -- -- -- -- -- -- -- -- -- Changes following the 2010 Census On December 21, 2010 the U.S. Census Bureau released its official apportionment results for congressional representation. The changes were in effect for the U.S. elections in 2012. Gain four Gain two Gain one No change Lose one Lose two 1. Texas 1. Florida 1. Arizona 2. Georgia 3. Nevada 4. South Carolina 5. Utah 6. Washington ( 32 states ) 1. Illinois 2. Iowa 3. Louisiana 4. Massachusetts 5. Michigan 6. Missouri 7. New Jersey 8. Pennsylvania 1. New York 2. Ohio + 4 + 2 + 6 − 8 − 4 + 12 seats gained total − 12 seats lost total Past increases The size of the U.S. House has increased and decreased as follows : 1789 -- 1800 Date Size Change Citation Comments March 4, 1789 59 n / a Const. Art. I, § 2, cl. 3 Seats apportioned by the Constitution November 21, 1789 64 5 North Carolina ratified the Constitution with the seats apportioned by the Constitution May 29, 1790 65 Rhode Island ratified the Constitution with the seat apportioned by the Constitution March 4, 1791 67 1 Stat. 191 Vermont admitted June 1, 1792 69 Kentucky admitted March 4, 1793 105 36 Apportionment Act of 1792, 1 Stat. 253 Apportionment of the First Census June 1, 1796 106 1 Stat. 491 Tennessee admitted 1801 -- 1820 Date Size Change Citation Comments March 1, 1803 107 2 Stat. 175 Ohio admitted. March 4, 1803 142 35 2 Stat. 128 Apportionment of the Second Census. April 30, 1812 143 2 Stat. 703 Louisiana admitted. March 4, 1813 182 39 2 Stat. 669 Apportionment of the Third Census. December 11, 1816 183 3 Stat. 290 Indiana admitted. December 10, 1817 184 3 Stat. 349 Mississippi admitted. December 3, 1818 185 3 Stat. 430 Illinois admitted. December 14, 1819 186 3 Stat. 492 Alabama admitted. March 15, 1820 3 Stat. 555 Maine admitted, 7 seats transferred from Massachusetts 1821 -- 1840 Date Size Change Citation Comments August 10, 1821 187 3 Stat. 547 Missouri admitted March 4, 1823 213 26 3 Stat. 651 Apportionment of the Fourth Census March 4, 1833 240 27 4 Stat. 516 Apportionment of the Fifth Census June 15, 1836 241 5 Stat. 51 Arkansas admitted January 26, 1837 242 5 Stat. 50 Michigan admitted 1841 -- 1853 Date Size Change Citation Comments March 4, 1843 223 19 5 Stat. 491 Apportionment of the Sixth Census, the only time the size of the House was reduced, except for the minor readjustments in 1863 and 1963. March 3, 1845 224 5 Stat. 743 Florida admitted. December 29, 1845 226 5 Stat. 798 Texas annexed and admitted. December 28, 1846 228 5 Stat. 743 9 Stat. 52 Iowa admitted. May 29, 1848 230 9 Stat. 58 9 Stat. 235 Wisconsin admitted. March 4, 1849 231 9 Stat. 235 Wisconsin given another seat. September 9, 1850 233 9 Stat. 452 California admitted. March 4, 1853 9 Stat. 432 Apportionment of the Seventh Census. 234 10 Stat. 25 Additional seat apportioned to California The 1850 Apportionment bill provided a method to be used in future reapportionments, as well as establishing the then - current 233 as the number of seats to be apportioned after future censuses. Due to census returns being incomplete in California, an additional act provided that California retain the same representation it had when admitted, until a new census could be taken. California would otherwise have lost one seat, and so the total number of seats was increased by one to 234. 1854 -- 1880 Date Size Change Citation Comments May 11, 1858 236 11 Stat. 166 Minnesota admitted. February 14, 1859 237 11 Stat. 383 Oregon admitted. January 29, 1861 238 11 Stat. 269 Kansas admitted June 2, 1862 239 12 Stat. 411 California apportioned an extra seat March 4, 1863 233 6 9 Stat. 432 Apportionment of the Eighth Census, in accordance with the 1850 act, which provided for an apportionment of 233 seats 241 8 12 Stat. 353 Supplemental apportionment of 8 seats, for an overall increase of 2 seats in the 38th Congress June 20, 1863 12 Stat. 633 West Virginia admitted, three seats transferred from Virginia October 31, 1864 242 13 Stat. 32 Nevada admitted March 1, 1867 243 14 Stat. 391 Nebraska admitted March 4, 1873 283 40 17 Stat. 28 Apportionment of the Ninth Census, replacing the 1850 act 292 9 17 Stat. 192 Supplemental apportionment added one seat each for nine states August 1, 1876 293 13 Stat. 34 Colorado admitted 1881 -- 1900 Date Size Change Citation Comments March 4, 1883 325 32 47th Congress, ch. 20, 22 Stat. 5 Apportionment of the Tenth Census. November 2, 1889 328 North and South Dakota admitted, with one and two seats respectively. November 8, 1889 329 Montana admitted. November 11, 1889 330 Washington admitted. July 3, 1890 331 Idaho admitted. July 10, 1890 332 Wyoming admitted. March 4, 1893 356 24 Apportionment Act of 1891 ; 26 Stat. 735 Apportionment of the Eleventh Census. January 4, 1896 357 Utah admitted. 1901 -- present Date Size Change Citation Comments March 4, 1903 386 29 Apportionment Act of 1901, 31 Stat. 733 Apportionment of the Twelfth Census November 16, 1907 391 5 Oklahoma Enabling Act ; 34 Stat. 277 Oklahoma admitted January 6, 1912 393 Apportionment Act of 1911, Sec. 2 ; New Mexico Enabling Act New Mexico admitted February 14, 1912 394 Apportionment Act of 1911, Sec. 2 Arizona admitted March 4, 1913 435 41 Apportionment Act of 1911, Pub. L. 62 -- 5, 37 Stat. 13 Apportionment of the Thirteenth Census January 3, 1959 436 Alaska Statehood Act Alaska admitted August 21, 1959 437 Hawaii Admission Act Hawaii admitted January 3, 1963 435 Reapportionment Act of 1929, ch. 28, 46 Stat. 26, 2 U.S.C. § 2a Apportionment of the Eighteenth Census Note : The Reapportionment Act of 1929 stated that the `` then existing number of Representatives '' would be apportioned after each census, which would have dictated an apportionment of 437 seats, but the Alaska Statehood Act and Hawaii Admission Act explicitly stated that the new seats were temporary increases See also Apportionment paradox Congressional Apportionment Amendment Gerrymandering List of U.S. states by population List of U.S. states by historical population ( tables of state populations since 1790 ) Redistricting Electoral vote changes between United States presidential elections United States Congress Notes Delegate counts in italics represent temporary counts assigned by Congress until the next decennial census or by the U.S. Constitution in 1789 until the first U.S. Census. Elections held in the year of a census use the apportionment determined by the previous census. ^ Jump up to : Kristin D. Burnett ( 2011 - 11 - 01 ). `` Congressional Apportionment ( 2010 Census Briefs C2010BR - 08 ) '' ( PDF ). U.S. Department of Commerce, Economics and Statistics Administration. Retrieved 2015 - 02 - 25. Jump up ^ The populations of Washington, D.C. and federal territories are not included in this figure. Jump up ^ 2 U.S.C. § 2c Jump up ^ 28 U.S.C. § 2284 ( a ) Jump up ^ Rendered moot by the Revenue Act of 1924 and Indian Citizenship Act of 1924. Jump up ^ Bush signs federalization bill, Agnes E. Donato, Saipan Tribune, May 10, 2008. Jump up ^ `` Fair Representation, Meeting The Ideal of One Man One vote '' - Michel Balinski and H. Peyton Young -- Page 51 Jump up ^ ( 1 ) Jump up ^ George Will Called Me An Idiot, Jonah Golderg, National Review, January 15, 2001. Jump up ^ Madison 's notes on the Constitutional Convention - Tuesday September 17, 1787 ^ Jump up to : The Federalist # 55 Jump up ^ `` Constitutional Amendments Not Ratified ''. United States House of Representatives. Archived from the original on 27 September 2007. Retrieved 2007 - 09 - 30. Jump up ^ House of Representatives ? Hardly., Alcee Hastings, May 21, 2001. Jump up ^ Marimow, Ann E. ; Pershing, Ben ( April 21, 2010 ). `` Congressional leaders shelve D.C. voting rights bill ''. The Washington Post. Jump up ^ `` Congressional Apportionment - Historical Perspective ''. U.S. Census Bureau. Retrieved 27 October 2013... Jump up ^ `` The History of Apportionment in America ''. American Mathematical Society. Retrieved 2009 - 02 - 15. Jump up ^ `` 2 USC § 2a ''. Cornell University Law School, Legal Information Institute. Retrieved 2008 - 05 - 13. Jump up ^ `` Computing Apportionment ''. U.S. Census Bureau. Retrieved 2009 - 02 - 14. Jump up ^ Edward V Huntington ( 1921 ). `` The Mathematical Theory of the Apportionment of Representatives ''. Proceedings of the National Academy of Sciences of the United States of America. 7 ( 4 ) : 123 -- 7. PMC 1084767. PMID 16576591. doi : 10.1073 / pnas. 7.4. 123. Jump up ^ `` Congressional Apportionment ''. NationalAtlas.gov. U.S. Department of the Interior. Archived from the original on 2008 - 10 - 30. Retrieved 2009 - 02 - 14. Jump up ^ `` PRIORITY VALUES FOR 2010 CENSUS '' ( PDF ). U.S. Bureau of the Census. Retrieved 2012 - 06 - 07. Jump up ^ `` Census 2000 Ranking of Priority Values ''. U.S. Bureau of the Census. 2001 - 02 - 21. Retrieved 2008 - 05 - 13. Jump up ^ Congress failed to pass any reapportionment to implement the 1920 United States Census so despite population shift, distribution of seats from 1913 remained in effect until 1933. Jump up ^ `` APPORTIONMENT POPULATION AND NUMBER OF REPRESENTATIVES, BY STATE : 2010 CENSUS '' ( PDF ). US Census. 2010 - 12 - 21. Retrieved 2013 - 02 - 23. Jump up ^ The Size of the U.S. House of Representatives and its Constituent State Delegations, thirty-thousand.org. Jump up ^ Both acts included the phrasing That such temporary increase in the membership shall not operate to either increase or decrease the permanent membership of the House of Representatives as prescribed in the Act of August 8, 1911 ( 37 Stat. 13 ) nor shall such temporary increase affect the basis of apportionment established by the Act of November 15, 1941 ( 55 Stat. 761 ; 2 U.S.C., sec. 2a ), for the Eighty - third Congress and each Congress thereafter. References Balinski, Michael L. ; Young, H. Peyton ( 1982 ). Fair Representation : Meeting the Ideal of One Man, One Vote. New Haven, CT : Yale University Press. ISBN 0 - 8157 - 0090 - 3. Foster, Robert ( 1895 ). Commentaries on the Constitution of the United States : Historical and Judicial. 1. Boston : The Boston Book Co. pp. 329 -- 446. Hamilton, Alexander ; Madison, James ; Jay, John ( 1831 ). The Federalist. Hallowell : Glazier, Masters & Co. ISBN 0 - 8239 - 5735 - 7. Edelman, Paul H. ( 2006 ). `` Getting the Math Right : Why California Has Too Many Seats in the House of Representatives ''. Vanderbilt Law Review. Nashville : Vanderbilt University. 102 ( March ) : 297. Kromkowski, Charles A. ; Kromkowski, John A. ( 1991 ). `` Why 435 ? A Question of Political Arithmetic '' ( PDF ). Polity. 24 ( Fall 1991 ) : 129 -- 145. JSTOR 3234988. doi : 10.2307 / 3234988. Retrieved 2013 - 10 - 17. Agnew, Robert A. ( 2008 ). `` Optimal Congressional Apportionment '' ( PDF ). American Mathematical Monthly. Mathematical Association of America. 115 ( April ) : 297 -- 303. JSTOR 27642473. Further reading Stinebrickner - Kauffman, Taren ( 2004 ). `` Counting Matters : Prison Inmates, Population Bases, and `` One Person, One Vote '' ``. Virginia Journal of Social Policy & the Law. Chicago : Virginia Journal of Social Policy & the Law. 11 ( Winter ) : 229. External links Congressional Apportionment by the U.S. Census Bureau Thirty-thousand.org Commentaries and More Information on Increasing U.S. House Size. Retrieved from `` https://en.wikipedia.org/w/index.php?title=United_States_congressional_apportionment&oldid=807230349 '' Categories : Demographics of the United States United States House of Representatives United States congressional districts Hidden categories : Articles containing potentially dated statements from 2008 All articles containing potentially dated statements Talk Contents About Wikipedia Simple English Edit links This page was last edited on 26 October 2017, at 18 : 40. Text is available under the Creative Commons Attribution - ShareAlike License ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia ® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization. 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Question: when is the number of congressional districts per state determined
Answer: no later than January 25 of the year immediately following the census