The official City of Chicago Data Portal updated these files on April 6, 2015. Use them instead!
These Chicago wards and precincts boundary shapefiles are effective as of 2015. As of Thursday, February 26, 2015, the shapefiles on the City of Chicago’s data portal are stale—they are the boundaries from before the city council voted to redraw them in 2012.
The original source material was provided by the Chicago Board of Elections in response to a FOIA request, in the form of 50 shapefiles corresponding to precinct boundaries and attributes in each Chicago ward.
I applied minimal post-processing to produce various formats, and to generate ward boundaries by aggregating precincts and unioning their geometries.
For more detailed background on the source and production of these shapefiles, read this blog post.
Having trouble with these files? Email Paul Smith at firstname.lastname@example.org.