Here is a link I found.
http://www.dogfriendly.com/server/tr...42playgr.shtml
It says...
Grant Park Bark Park opened on July 15, 2006 and is located in the famous Grant Park along the lake in Chicago. It is fully fenced and is about 18,000 square feet in size. There is access to the dog park from Columbus Avenue and from the 11th Street bridge. The park is maintained by the South Loop Dog P.A.C. All dogs that use the Chicago dog parks are required to have an annual permit. The permits currently cost $5 per dog. You will have to visit an approved location to get a permit. Proof of certain vaccinations are also required.