PLSS Maps

http://nationalatlas.gov/articles/boundaries/a_plss.html

The Public Land Survey System (PLSS) is a way of subdividing and describing land in the United States.  The PLSS is a rectangular survey system that typically divides the land into 6-mile square townships, which are further subdivided into 1-mile square sections.  The above map shows the French arpent land division in Louisiana.