Dixie Highway

 I saw a PBS show about some Chicago history, and when they were on the south side, they talked about being on the Dixie Highway to Florida. Now I know the rest of the route.

1915 (source)
Billy Shockey: Also Western Ave. I believe it is the longest street in the United States.

I knew Western Avenue was the only street in Chicago that went all the way from the north border to the south border. I didn't realized that it went south of the Chicago border and continued as the Dixie Highway.

Satellite

Looking some more at the national map, I knew that Lincoln Highway (US30) went through Fort Wayne, IN. I didn't know that US-24 west of Fort Wayne was part of the initial national highway system.