Subdivision control has long been a central pillar of planning. Nonetheless, many American states statutorily exempt entire classes of land division from local subdivision control. This legal analysis therefore asks the following: Which land divisions are localities actually enabled by statute to regulate as "subdivisions"? Which are exempted from subdivision control? What are the implications for development and planning, particularly at the exurban fringe? This fifty-state review reveals diverse ways subdivisions are defined and particular divisions—involving no new streets, large parcels, or small numbers of lots—commonly exempted from regulation, and possible consequences for managing rural sprawl.