The total number of representatives is currently fixed at 435 by Public Law 62-5 of 1911, though Congress has the authority to change that number. Each representative serves for a two-year term and may be re-elected an unlimited number of times. The presiding officer of the House is known as the Speaker, and is elected by the members. The present House delegation by state are shown in the article List of U.S. states by population.

The bicameral Congress arose from the desire of the Founders to create a House "of the people" that would represent public opinion, balanced by a more deliberative Senate that would represent the governments of the individual states, and would be less susceptible to variations of mass sentiment. The House is often considered to be the "lower house," with the Senate as the "upper house," although the United States Constitution does not use such language. The Constitution provides that the approval of both houses is necessary for the passage of legislation.

Because its members are generally elected from smaller (approximately 693,000 residents as of 2007) and more commonly homogenous districts than those from the Senate, the House is generally considered a more partisan chamber. Many of the Founding Fathers intended the Senate (whose members were originally chosen by the state legislatures) to be a check on the popularly elected House, just as the House was to be a check on the Senate. The "advice and consent" powers (such as the power to approve treaties) were therefore granted to the Senate alone. The House was granted its own exclusive powers: the power to initiate revenue bills, impeach officials, and elect the President in electoral college deadlocks. The Senate, however, can propose amendments to spending bills and has exclusive authority to try impeached officials and choose the Vice President in an electoral college deadlock. The Senate and its members generally have greater prestige than the House because Senators serve longer terms (six years) in a smaller body and (in all but seven states) represent larger constituencies than Representatives.