This week I originally planned a double column, but I am pushing the answer to a "shocking" question to next week. Today I am answering a question from Hollie who wrote:
Q: I have heard many theories about how many city blocks equals one mile -- anywhere from eight to twelve blocks per mile. And, some people say that once you get to the north side the ratio is different than it is downtown. So, how many city blocks equal one mile in Chicago, and does the ratio change with what area of the city you are in?
Thanks, Hollie, for the question. The general rule is eight blocks equal a mile, provided you are counting the side of the block that is 660 feet long rather than the 330 foot side. But why is this true?
Chicago was planned on a grid system with each grid measuring one square mile. Eight standard city blocks fit within a grid, although many times these blocks are further subdivided (such as in the downtown area) which can seem to throw off the eight blocks rule. So, rather than counting each and every block, the easiest way to measure your distance is to guide yourself by the city's numbering system.A standard city block in Chicago has 100 potential address numbers. Following the grid system, then, one mile equals 800 numbers. So, here's how it works:
Many of Chicago's major streets signify either a half mile or mile marker on the grid. The starting point for Chicago's numbering system is the intersection of State and Madison in the Loop. Traveling north from this intersection, the first half mile point is Kinzie, which is 400 North (half of 800, get it?). You'll have traveled a mile when you reach Chicago Avenue (800 North). Using this formula, figuring out the rest of the half mile and mile streets is pretty easy. Continuing north, the next markers are Division (1200 N), North Ave. (1600 N), Armitage (2000 N), Fullerton (2400 N), etc.
The same rule holds true if you are traveling east and west. Going east, the first half mile street is King Dr. at 400 East, and the first mile street is Cottage Grove at 800 East. Traveling west from State and Madison, the streets include Stewart Ave. (400 W), Halsted (800 W), Racine (1200 W), Ashland (1600 W), etc.
One notable exception is directly south of Madison where a numbering discrepancy exists for the first three miles south. Instead of 800 South, the first "mile" street south of Madison is Roosevelt at 1200 South. The second mile south is Cermak at 2200 South, and the third mile is 31st Street (3100 S). After 31st, however, the 800 rule applies again, and the next mile markers are at 39th, 47th, Garfield (5500 S), etc.
So, by performing some simple arithmetic, figuring out how far you've traveled in Chicago is a fairly simple matter. In general, just count how many "hundreds" you have traveled and remember that eight hundreds equals a mile.
I would love to get into the history of urban planning in Chicago, but that will have to be the subject of another column.
Ask me a question. Now. Don't make me come over there. Send your questions to firstname.lastname@example.org and it may be featured in a future column.
Next week: Finally, the "shocking" answer.