The Bureau of Land Management (BLM) cadastral survey program is responsible for the official boundary surveys for all federal agencies in the U.S. that together manage over 700 million acres. The Public Land Survey System also called the Rectangular Survey System is the foundation for many survey-based land information systems Download PLSS GIS shapefiles. To select and download data, select the Map Viewer and Download button. See http://www.geocommunicator.gov/GeoComm/lsis_home/home/index.html