When the first Congress met in 1789, there were 59 Representatives in the House of Representatives. As the number of states increased and as the population grew, the number of Representatives increased significantly. A law passed in 1911 fixed the size of the House of Representatives at 435 members. Members of the House are up for reelection every two years. The number of persons representing each state depends upon its population as reported in the Nation's decennial census counts. Each state is divided into congressional districts accordingly. There is a Representative for every congressional district and every state has at least one congressional district.

In order to be elected to the House of Representatives one must be at least 25 years old by the time one takes the oath of office, a citizen of the U.S. for at least seven years, and a resident of the state from which one is elected. These qualifications were established in Article I, Section 2 of the Constitution.

Most states have primary elections to decide which candidates will be on the November general election ballot. Some state parties hold conventions in conjunction with the primary. If a candidate is unopposed, there may not be a primary election. Those who represent a major political party are automatically placed on a state's primary ballot. Minor party candidates are chosen by their party's rules while independent candidates nominate themselves. Independent candidates and those representing minor parties must meet various state requirements to be placed on the general election ballot. An example of this would be to submit a petition with signatures from a certain number of registered voters.

Senate and House of Representative elections differ in who votes for the candidates. All eligible voters within a state may vote for Senator. A Representative is elected by only those eligible voters residing in the congressional district that the candidate will represent. Election winners are decided by the plurality rule. That is, the person who receives the highest number of votes wins. This may not necessarily be a majority of the votes.