List of U.S. states and territories by population
The states and territories included in the United States Census Bureau's statistics for the United States (population, ethnicity, religion, and most other categories) include the 50 states and the District of Columbia (Washington, D.C.). Separate statistics are maintained for the five permanently inhabited territories of the United States (Puerto Rico, Guam, the U.S. Virgin Islands, American Samoa, and the Northern Mariana Islands). Method. The United States Census counts the persons residing in the United States including citizens, non-citizen permanent residents and non-citizen long-term visitors. Civilian and military federal  employees serving abroad and their dependents are counted in their home state. Electoral apportionment. House of Representatives. Based on the decennial census, each state is allocated a portion of the 435 fixed seats in the United States House of Representatives, with each state guaranteed at least one. The allocation is based on each state's proportion of the combined population of the fifty states (not including the District of Columbia, Guam, American Samoa, the Northern Mariana Islands, Puerto Rico, or the United States Virgin Islands). Electoral College. The Electoral College, every four years, elects the President and Vice President of  the United States based on the popular vote in each state and the District of Columbia. Each state's number of votes in the Electoral College is equal to its number of members in the Senate plus members in the House of Representatives. The Twenty-third Amendment to the United States Constitution additionally grants the District of Columbia (D.C.), which is not part of any state, as many Electoral College votes as it would have if it "were" a state, while having no more votes than the least populous state (currently, Wyoming). Since the U.S. Constitution guarantees every state at  least one member of the U.S. House of Representatives and two members of the U.S. Senate, every state has at least three Electoral College votes. Thus, the Electoral College has 538 members (100 senators, plus 435 representatives, plus 3 members for the District of Columbia). Territories of the United States such as Puerto Rico are not included in the Electoral College: people in those territories cannot vote directly for the President of the United States, although they may participate in the partisan nominating primaries and caucuses. State and territory rankings. Column header abbreviations: <nowiki>*</nowiki> — non-voting member  of the House of Representatives. Summary of population by region. Column header abbreviations: # = Rank, Geo. = Geographic