Missouri's third congressional district is in the eastern and central portion of the state.

It stretches from the southern part of Columbia (including the University of Missouri) and the state capital of Jefferson City in the west to St. Charles County (including the large suburbs of St. Charles, St. Peters and Wentzville) and western Jefferson County in the east.

Its best-known congressman was Dick Gephardt, who represented the district for 28 years until his retirement from Congress.

Following a dramatic drop in the population of St. Louis in the 2010 United States census, Missouri lost a congressional seat effective in 2013.

The 3rd's home base in St. Louis would be absorbed by Missouri's 1st congressional district.