Article I of the Constitution establishes the legislative branch. Section 1 reads:

All legislative Powers herein granted shall be vested in a Congress of the United States, which shall consist of a Senate and House of Representatives.

The remaining sections of Article I go on to list specifics about how Congress must be formed and run. The first section, as we read above, makes our Congress bicameral. Bicameral means that Congress has two houses: the House of Representative and the Senate. We have the two houses of Congress due to a compromise made by the Founding Fathers during the Constitutional Convention. Delegates to the Constitutional Convention from larger and more populated states argued for the Virginia Plan, which called for congressional representation to be based on a state's population. Fearing domination, delegates from smaller states were just as adamant for equal representation and supported the New Jersey Plan, which proposed that each state should have one vote, regardless of population. Roger Sherman, a delegate from Connecticut, proposed the bicameral legislature structure. The Great Compromise, along with some other provisions, resulted in the creation of two houses, with representation based on population in one (the House of Representatives) and with equal representation in the other (the Senate).

Some of the powers granted to Congress in Article I are: regulating commerce, passing laws, the power to lay taxes, to establish Post Offices and post roads, and to “define and punish Piracies and Felonies committed on the high Seas”, among others. Article I also states the requirements a person must meet to run for Congress, establishes the Vice President as President of the Senate, and places limitations on some of their actions.