The County's system of tax maps is based on the Illinois Public Land Survey System (PLSS). In the PLSS, each township is divided into 36 sections, and each section into four quarter-sections. A quarter-section is further divided into two tax map sheets, often called "pages". Each tax map (1/4 mile by 1/2 mile) represents the east or west half of one quarter-section, and typically there are eight tax maps per section.

Cook County GIS Dept map of Barrington Township in a pdf format. Includes streets and municipalities.

The Public Land Survey System (PLSS) forms the foundation of Cook County's cadastral system for identifying and locating land records. Tax parcels are identified using township and section notation, in a modified format. This PLSS feature data set is intended to correspond to tax pages in the Cook County Assessor's Tax Map book (current as of tax year 2000 for 66% of the County and as of tax year 2001 for the remaining 33% of the County), and should not be used for measurement or surveyor purposes. In addition, the parcel attributes PINA (area/township) and PINSA (subarea/section) do not necessarily correspond to the PLSS township and section polygon in which a given parcel resides. The PLSS data is modeled as a single composite network coverage that encompasses townships (area), sections (subarea), quarter sections, and half quarter section.

All Cook County Tweets, starting in 2011 to 12/31/2013. As measured by Crowdbooster.

This Municipality feature class interprets the location and describes the boundaries of all municipalities and unincorporated areas within the borders of Cook County. Attribution for this feature class includes a municipality name and agency description.

Information updated on July 23, 2015.

Cook County is home to over 130 municipalities. Our list gives each one along with the City Hall Address and URL.

Annual salaries paid to employees by the Cook County Comptroller as of March 5, 2013. Does not include deduction for furlough or closure days for employees subject to furloughs and closures. Does not include amounts paid by other governmental entities. For 2014 salaries see https://datacatalog.cookcountyil.gov/resource/hdna-35se

2013 Appropriation by Department and Account. Data from 01/10/13.