# List of principal and guide meridians and base lines of the United States

The following are the principal and guide meridians and base lines of the United States, with the year established and a brief summary of what areas' land surveys are based on each.

## List of meridians

Primarily from the United States Government Printing Office Style Manual. State names usually signify only parts of each listed state, unless otherwise indicated.
Based on the BLM manual's 1973 publication date, and the reference to Clarke's Spheroid of 1866 in section 2-82, coordinates appear to be in the NAD27 datum.

### Principal Meridians

| Meridian | Longitude | Associated Baseline | Latitude | Adopted | Area surveyed |
| First principal | 84°48′11″W | | 40°59′22″N | 1819 | Ohio (NW) |
| First principal | 84°48′11″W | | 40°59′22″N | 1819 | Indiana (sliver of SE) |
| Second principal | 86°27′21″W | | 38°28′14″N | 1805 | Illinois (far E) |
| Second principal | 86°27′21″W | | 38°28′14″N | 1805 | Indiana (almost all) |
| Third principal | 89°08′54″W | Centralia | 38°28′27″N | 1805 | Illinois (most) |
| Fourth principal | 90°27′11″W | Beardstown | 40°00′50″N | 1815 | Illinois (W of Illinois River and 3rd principal meridian) |
| Fourth principal (extended) | 90°25′37″W | Illinois–Wisconsin border | 42°30′27″N | 1831 | Minnesota (NE) |
| Fourth principal (extended) | 90°25′37″W | Illinois–Wisconsin border | 42°30′27″N | 1831 | Wisconsin (all) |
| Fifth principal | 91°03′07″W | | 34°38′45″N | 1815 | Arkansas (all) |
| Fifth principal | 91°03′07″W | | 34°38′45″N | 1815 | Iowa (all) |
| Fifth principal | 91°03′07″W | | 34°38′45″N | 1815 | Minnesota (most) |
| Fifth principal | 91°03′07″W | | 34°38′45″N | 1815 | Missouri (all) |
| Fifth principal | 91°03′07″W | | 34°38′45″N | 1815 | North Dakota (all) |
| Fifth principal | 91°03′07″W | | 34°38′45″N | 1815 | South Dakota (E half) |
| Sixth principal | 97°22′08″W | | 40°00′07″N | 1855 | Colorado (most) |
| Sixth principal | 97°22′08″W | | 40°00′07″N | 1855 | Kansas (all) |
| Sixth principal | 97°22′08″W | | 40°00′07″N | 1855 | Nebraska (all) |
| Sixth principal | 97°22′08″W | | 40°00′07″N | 1855 | South Dakota (some of S) |
| Sixth principal | 97°22′08″W | | 40°00′07″N | 1855 | Wyoming (most) |
| Black Hills | 104°03′16″W | Black Hills | 43°59′44″N | 1878 | South Dakota (W) |
| Boise | 116°23′35″W | | 43°22′21″N | 1867 | Idaho (all) |
| Chickasaw | 89°14′47″W | | 35°01′58″N | 1833 | Mississippi |
| Choctaw | 90°14′41″W | Choctaw | 31°52′32″N | 1821 | Mississippi |
| Cimarron | 103°00′07″W | | 36°30′05″N | 1881 | Oklahoma (panhandle) |
| Copper River | 145°18′37″W | | 61°49′04″N | 1905 | Alaska |
| Fairbanks | 147°38′25.949″W | | 64°51′50.048″N | 1910 | Alaska |
| Gila and Salt River | 112°18′19″W | | 33°22′38″N | 1865 | Arizona (most) |
| Humboldt | 124°07′10″W | | 40°25′02″N | 1853 | California |
| Huntsville | 86°34′16″W | | 34°59′27″N | 1807 | Alabama |
| Huntsville | 86°34′16″W | | 34°59′27″N | 1807 | Mississippi |
| Indian | 97°14′49″W | | 34°29′32″N | 1870 | Oklahoma (most) |
| Kateel River | 158°45′31.014″W | | 65°26′16.374″N | 1956 | Alaska |
| Louisiana | 92°24′55″W | | 31°00′31″N | 1807 | Louisiana |
| Michigan | 84°21′53″W | | 42°25′28″N | 1815 | Michigan |
| Michigan | 84°21′53″W | | 42°25′28″N | 1815 | Ohio |
| Montana | 111°39′33″W | | 45°47′13″N | 1867 | Montana |
| Mount Diablo | 121°54′47″W | | 37°52′54″N | 1851 | California |
| Mount Diablo | 121°54′47″W | | 37°52′54″N | 1851 | Nevada |
| Navajo | 108°31′59″W | Navajo | 35°44′56″N | 1869 | Arizona (NE) |
| Navajo | 108°31′59″W | Navajo | 35°44′56″N | 1869 | New Mexico (NW, formerly) |
| New Mexico principal | 106°53′12″W | | 34°15′35″N | 1855 | New Mexico |
| New Mexico principal | 106°53′12″W | | 34°15′35″N | 1855 | Colorado (SW) |
| St. Helena | 91°09′36″W | | 30°59′56″N | 1819 | Louisiana |
| St. Stephens | 88°01′20″W | St. Stephens | 30°59′51″N | 1805 | Alabama |
| St. Stephens | 88°01′20″W | St. Stephens | 30°59′51″N | 1805 | Mississippi |
| Salt Lake | 111°53′27″W | | 40°46′11″N | 1855 | Utah (most) |
| San Bernardino | 116°55′48″W | | 34°07′13″N | 1852 | California |
| San Bernardino | 116°55′48″W | | 34°07′13″N | 1852 | Arizona (some townships) |
| Seward | 149°21′26″W | | 60°07′37″N | 1911 | Alaska |
| Tallahassee | 84°16′38″W | | 30°26′03″N | 1824 | Florida |
| Tallahassee | 84°16′38″W | | 30°26′03″N | 1824 | Alabama |
| Uintah | 109°56′06″W | | 40°25′59″N | 1875 | Utah (part of NE) |
| Umiat | 152°00′04.551″W | | 69°23′29.654″N | 1956 | Alaska |
| Ute | 108°31′59″W | | 39°06′23″N | 1880 | Colorado |
| Washington (Mississippi) | 91°09′36″W | | 30°59′56″N | 1803 | Mississippi |
| Willamette | 122°44′34″W | Willamette | 45°31′11″N | 1851 | Oregon |
| Willamette | 122°44′34″W | Willamette | 45°31′11″N | 1851 | Washington |
| Wind River | 108°48′49″W | | 43°00′41″N | 1875 | Wyoming (part of W) |

### Guide Meridians

| Meridian | Longitude | Associated Baseline | Area surveyed | Notes |
| Ashley guide meridian | | | Utah | |
| Beaverhead guide meridian | | | Montana | |
| Belt Mountain guide meridian | | | Montana | |
| Big Hole guide meridian | | | Montana | |
| Bitterroot guide meridian | | | Montana | |
| Boulder guide meridian | | | Montana | |
| Browning guide meridian | | | Montana | |
| Buffalo Creek guide meridian | | | Montana | |
| Carson River guide meridian | | | Nevada | |
| Castle Valley guide meridian | | | Utah | |
| Colorado guide meridian | | | Utah | |
| Columbia guide meridian | | | Washington | |
| Colville guide meridian | | | Washington | |
| Coulson guide meridian | | | Montana | |
| Deer Lodge guide meridian | | | Montana | |
| Deschutes meridian | | | Oregon | |
| Emery Valley guide meridian | | | Utah | |
| Flathead guide meridian | | | Montana | |
| Fort Belknap guide meridian | | | Montana | |
| Fremont Valley guide meridian | | | Utah | |
| Grand River guide meridian | | | Utah | |
| Grande Ronde guide meridian | | | Oregon | |
| Green River guide meridian | | | Utah | |
| Haystack Butte guide meridian | | | Montana | |
| Helena guide meridian | | | Montana | |
| Henry Mountain guide meridian | | | Utah | |
| Horse Plains guide meridian | | | Montana | |
| Humboldt River guide meridian | | | Nevada | |
| Jefferson guide meridian | | | Montana | |
| Judith guide meridian | | | Montana | |
| Kanab guide meridian | | | Utah | |
| Kolob guide meridian | | | Utah | |
| Little Porcupine guide meridian | | | Montana | |
| Maginnis guide meridian | | | Montana | |
| Musselshell guide meridian | | | Montana | |
| New Mexico guide meridian | | | New Mexico and Colorado | |
| Panguitch guide meridian | | | Utah | |
| Passamari guide meridian | | | Montana | |
| Pine Valley guide meridian | | | Utah | |
| Red Rock guide meridian | | | Montana | |
| Reese River guide meridian | | | Nevada | |
| Ruby Valley guide meridian | | | Nevada | |
| Sevier Lake guide meridian | | | Utah | |
| Shields River guide meridian | | | Montana | |
| Smith River guide meridian | | | Montana | |
| Snake Valley guide meridian | | | Utah | |
| Square Butte guide meridian | | | Montana | |
| Sweet Grass guide meridian | | | Montana | |
| Teton guide meridian | | | Montana | |
| Valley Creek guide meridian | | | Montana | |
| Wah Wah guide meridian | | | Utah | |
| Whatcom County guide meridian | 122°30' | Willamette Meridian | Whatcom County, Washington | 12 miles east of Willamette Meridian, much of which is in Salish Sea at this latitude. Followed by Guide Road / Old Guide Road / Washington State Route 539 in Whatcom County, Meridian Street in Bellingham, Washington. |
| Willow Springs guide meridian | | | Utah | |
| Yantic guide meridian | | | Montana | |
| Yellowstone guide meridian | | | Montana | |

## Ohio Lands

Some parts of the Ohio Lands (now Ohio) were laid out in survey townships, but based on other points not listed above:
* Base Line of the United States Military Survey (1797)
* Great Miami River baseline (1798)
* Ohio River (1785) — also part of Indiana
* Muskingum River baseline (1800)
* Scioto River baseline (1799)
* Twelve Mile Square Reserve (1805)