Lake Street is an east–west street in Chicago and part of its suburbs. A portion of Lake Street is designated as U.S. Route 20. Lake Street begins in downtown Chicago and travels west to the eastern terminus of the Elgin Bypass around suburban Elgin. The street travels west through the city and then begins to travel in a northwest fashion through several suburbs. The street is a distance of roughly .
In South Austin, it ends crosses under the Union Pacific and continues southeast with the CTA Green Line tracks in the middle. It passes through Garfield Park and continues east toward downtown Chicago. It crosses railroad tracks and the CTA tracks then elevate as they are part of the Chicago "L" system. It intersects major streets in Chicago and has a partial interchange with the Kennedy Expressway and Interstates 90 and 94. It then continues east and ends at Stetson Avenue. In 1938, U.S. 20 was moved onto Mannheim Road and La Grange Road. The remaining segment of Lake Street became City U.S. 20. In 1960, it was renamed to Business U.S. 20. In 1968, all designations were dropped from Lake Street east of Mannheim Road.