[aruanan]

Then ya got yer diagonals: Lincoln, Milwaukee Ave., Elston. . . .

And that street that cuts from somewhere around Western southwest to past Cicero, maybe to Harlem or beyond. I wonder if these diagonals represent some of the oldest extant roadways in Chicago.

[carlo3b]

I think that is the Southwest Highway.. I have always wondered why those roads were so different, from an otherwise perfect grid.

[Chi-townChief]

Columbus / Southwest Highway runs all the way out to Lockport as Illinois 7. These streets are all angled to follow the river as is the Stevenson I-55.