I need the classification of residential, commercial and mixed areas of cities in the US as defined by mayor councils. Where can I find the zoning GIS maps/ shapefiles online?
You can Find the information city wise here: http://us-city.census.okfn.org/dataset/zoning
This is free data and can be downloaded in bulk as well. One of the sample of zoning is as provided here
If you have a budget as well then you can get the complete data on arcgis. Sample of the same in action can be viewed here
Bonus: You can have other detailed datasets like Demographic Statistics By Zip Code here