Straight dope chicago: Streets jog at North Avenue -- 10/08/2009

Cecil, I forgive you. And your explanation says all that needs to be said.:slight_smile:

Welcome to the Straight Dope Message Boards, hrmnn8r, we’re glad to have you with us.

When starting a thread, it’s helpful to others if you provide a link to the column: Providing the date is helpful, of course, but still will require searching time, so it’s more convenient for other readers to provide the link.

While I didn’t hear an explanation of North Avenue’s jogging (intersecting) streets as early as high school, I wonder what other lore exists for that stretch.

The one I heard was that there were two groups of surveyors and road builders, coming from opposite directions, aiming to meet at North Avenue, and a point of reference for one group was erroneous. By the time the error was discovered, it was too late to correct.

I wonder whether the subterranean infrastructure looks like the surface.


Welcome to the Straight Dope Message Board, rapidralph, we’re glad to have you with us.

Since there was another thread (sort of) on the same topic, I’ve merged your post into that thread, so all comments on the hiccup in streets at North Ave will be in the same place.

I think you were correct the first time.
When you go 24 miles north, you have to account for about 28.5’ for every mile you go past a baseline. In Illinois, that baseline, runs approximately through the center of the state. Assuming Chicago is about 60 miles from the baseline, that means the correction is 60*28.5, or about 1710’.

In case anybody is interested, a correction of 28.4669115 feet every 24 miles works out to …

a correction of 1.19 feet per mile,
or almost 1 foot, 2 and a quarter inches per mile.

If you like decimals, the correction is 14.23345575 inches per mile.

I’m devestated!!! I grew up in Chicago thinking that our streets were laid out in a perfect Cartesian grid aligned to the North Pole. In the house I grew up in, my bed was aligned to true north, or so I thought. I always slept well that way, and blamed insomnia on the inability to to line up my bed properly in other non-aligned residences since then. Now I learn that Chicago is 1.3 degrees off. How can I ever get another good night’s sleep, again? :wink: