Connecticut delegate Roger Sherman is credited with proposing the alternative of a "bicameral," or two-chambered Congress, made up of a Senate and a House of Representatives. Each state, suggested Sherman, would send an equal number of representatives to the Senate, and one representative to the House for each 30,000 residents of the state.
At the time, all the states except Pennsylvania had bicameral legislatures, so the delegates were familiar with the structure of Congress proposed by Sherman.
Shermans plan pleased delegates from both the large and small states and became known as the Connecticut Compromise of 1787, or the Great Compromise.
The structure and powers of the new U.S. Congress, as proposed by the delegates of the Constitutional Convention, were explained to the people by Alexander Hamilton and James Madison in the Federalist Papers 52-66.
Today, each state is represented in Congress by two Senators and a variable number of members of the House of Representatives based on the states population as reported in the most recent decennial census. The process of fairly determining the number of members of the House from each state is called "apportionment."
The first census in 1790 counted 4 million Americans. Based on that count, the total number of members elected to the House of Representatives grew from the original 65 to 106. The current House membership of 435 was set by Congress in 1911.