Where to acquire a dataset of US cities

Hi All!

This is my first time posting here, and love what bigger pockets has to offer. I am located in Illinois and want to zero in on target markets for my first multifamily property. 

I want a data set that breaks it down by county, zip code, median household income, average rent, etc. Is there a place I can find this without having to manually look up each city in Illinois? 

Please let me know! Looking forward to posting more.