The Blue Line is the term used in the U.S. state New York for the boundaries of the Adirondack and Catskill parks, within which can be found the state's Forest Preserve. The Constitution of New York requires that any property owned or acquired by the state in those parks "be forever kept as wild forest lands" and prohibits it from selling or transferring them in any way (save amending that section of the constitution to allow specific transactions).