The continuous platform connects Lake, Monroe, and Jackson stations, and is approximately 3,500 ft (1,100 m) long.

The State Street subway project was funded by New Deal programs established by Franklin D. Roosevelt during the Great Depression.

In 1937, the city of Chicago successfully applied for a federal grant and loan from the Works Progress Administration to fund the construction of two subway tunnels, the first of which would be built beneath State Street and the second beneath Milwaukee Avenue and Dearborn Street.

The subway extension was completed by January 25, 1990, but did not immediately enter passenger service.

Service through the State Street subway was stopped temporarily, while water was pumped out of the tunnels.