Election of the Congress
The word "Congress" refers to both the House of Representatives and the the Senate, which are both elected by direct election. "Congress" also refers to state legislators who make up a house of representatives for their respected states and are also elected by direct election. Congressional posts are meant to be representative of the constituency of the area they represent and are elected directly by voters within that district or state. Each type of congress has its own special procedure and logic behind its election process to explore.
The U.S. Senate is considered the upper body of the U.S. Congress and is made of of two senators from each state. Senators are elected by popular election within their represented state and serve a term of 6 years. Elections for the Senate are held every 2 years, with about a third of the Senate being up for re-election each time. A primary election is usually held in which each party runs several senatorial candidates to determine the one that will run in the general election. The winner of the general election is the candidate who receives the largest number of votes.
The US House
The U.S. House of Representatives is made up of a fixed number of 435 members that represent areas of the country by population, called single member districts. The single member districts change after each census to reflect an even distribution of population for each representative. Each single member district holds a general election after any primary elections to determine who their sole representative in the U.S. Congress will be. Elections are held every even numbered year in November and representatives serve for 2 years.
Individual states also have their own representative bodies, often referred to as State Congress, State Legislature, or State Assembly. Most states imitate the federal model of the 2-house system, but others, such as Nebraska, have only one. Most state congressional elections are held on the even numbered years and employ a population based representative system like the U.S. House, with district lines redrawn after the census. Terms of service of state representatives vary by state.