United States congressional apportionment
Effective date Size Change Legal provision Reason and/or comments
March 4 , 1789 59 n/a Const . Art . I , § 2 , cl . 3 Seats apportioned by the Constitution
November 21 , 1789 64 5 Const . Art . I , § 2 , cl . 3 North Carolina ratified the Constitution with the seats apportioned by the Constitution
May 29 , 1790 65 1 Const . Art . I , § 2 , cl . 3 Rhode Island ratified the Constitution with the seat apportioned by the Constitution
March 4 , 1791 67 2 1 Stat . 191 Vermont admitted
June 1 , 1792 69 2 1 Stat . 191 Kentucky admitted
March 4 , 1793 105 36 1 Stat . 253 ( Apportionment Act of 1792 ) Apportionment following the First Census
June 1 , 1796 106 1 1 Stat . 491 Tennessee admitted
March 1 , 1803 107 1 2 Stat . 175 Ohio admitted
March 4 , 1803 142 35 2 Stat . 128 Apportionment following the Second Census
April 30 , 1812 143 1 2 Stat . 703 Louisiana admitted
March 4 , 1813 182 39 2 Stat . 669 Apportionment following the Third Census
December 11 , 1816 183 1 3 Stat . 290 Indiana admitted
December 10 , 1817 184 1 3 Stat . 349 Mississippi admitted
December 3 , 1818 185 1 3 Stat . 430 Illinois admitted
December 14 , 1819 186 1 3 Stat . 492 Alabama admitted
March 15 , 1820 186 3 Stat . 555 Maine admitted , 7 seats transferred from Massachusetts
August 10 , 1821 187 1 3 Stat . 547 Missouri admitted
March 4 , 1823 213 26 3 Stat . 651 Apportionment following the Fourth Census
March 4 , 1833 240 27 4 Stat . 516 Apportionment following the Fifth Census
June 15 , 1836 241 1 5 Stat . 51 Arkansas admitted
List of apportionments
The size of the U.S. House of Representatives has increased and decreased as follows [ 40 ]
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 decennial census mandated by the United States Constitution. 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. The number of voting seats in the House of Representatives has been 435 since 1913, capped at that number by the Reapportionment Act of 1929 - except for a temporary (1959-1962) increase to 437 when Alaska and Hawaii were admitted into the Union. The size of a state's total congressional delegation also determines the size of its representation in the U.S. Electoral College, which elects the U.S. president.