Edward P. Brennan was the father of the city’s grid numbering system. Chairman of the City Club of Chicago’s Committee on Street Names, the freelance urban planner had another clever idea for keeping street names straight: naming them alphabetically, based on their distance west from the Indiana border. The first mile of streets would begin with A, the second with B, and so forth.

That would have required changing too many street names in established parts of town. But in 1911, Brennan’s system was partially adopted when the Northwest and West Sides were developed, beginning with K. The stretch of North Lawndale with streets such as Karlov, Kostner, and Kilpatrick is sometimes known as K-Town.

The plan was extended to the city limits, requiring some names that had nothing to do with Chicago, such as Ozanam (a 19th-century French historian) and Oketo (derived from the name of an Otoe chief). The plan goes all the way through P, ending with Pontiac, just east of Cumberland Avenue.

One thoroughfare that isn’t part of that scheme? Brennan Avenue, which runs between 96th and 98th Streets on the South Side — and is named for the old wizard of street nomenclature.

Send your questions about the Chicago area to emcclelland@chicagomag.com.