Chicago Cad File...Please Help!

Hello everyone

My name is Qianqian and I need help to find the Cad File of Chicago city( south of Chicago, near chinatown area)..... Please help!!! I am working on my thesis project right now and i need an more accurate version of the cad file.

Thanks so much! My email: qq.jessie.liu@gmail.com

Peace

Qianqian Liu