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.