A.) Census data (federal financial institution) database: you put in a Chicago address and you will get a local street map, plus certain census data for the related census tract. Click here
B.) Chicago Department of Zoning: type in a street address and you will get the building's tax i.d.number (pin number.) Click on the pin number you will find the zoning for that address, and for nearby addresses. If you click the 'map' section, you will see the local plot for the address, and for adjacent parcels. There is even a way of measuring the lot size. Click here
C.) Cook County Treasurer. Information on Property Taxes. Click here
D.) County Assessor's Office. Find a photograph and the property information number (PIN) for any property, just enter in a correct street address. Click here
E.)City of Chicago portal for ward maps: if the property tax system has you dazed, wait until you try and find out what ward you are in, and what its boundaries are. If you need city services, then you need to know what ward you are in. There is an invaluable magnifiying button for the maps that will help you find actual streets. (Big Download) - http://egov.cityofchicago.org/webportal/COCWebPortal/COC_EDITORIAL/Wards_overview_2.pdf