(PLSS) a rectangular survey system that utilizes 6-square-mile townships as its basic survey unit —note 1. the location of townships is controlled by baselines and meridians running parallel to latitude and longitude lines; townships are defined by range lines running parallel (north-south) to meridians and township lines running parallel (east-west) to baselines —note 2. the PLSS was established in the United States by the Land Ordinance of 1785This definition last updated 08/04/2008