The Raritan Highlands Compact is a cooperative organization of nine member municipalities in southwest Morris County (Chester Borough, Chester Township, Mendham Borough, Mendham Township, Mt. Arlington Borough, Mt. Olive Township, Randolph Township, Roxbury Township, Washington Township) and the County of Morris.

Associate members include the Upper Raritan Watershed Association, South Branch Watershed Association, New Jersey Water Supply Authority, the Regional Plan Association, and Morris Tomorrow. The central purpose of the Compact is to establish a common and comprehensive watershed model, and a set of model regulations and operating practices, in order to protect and improve water quality in the Raritan River and its aquifers.

In addition, members will work together to meet the new storm water regulations and to help each of the member towns carry out the water preservation purposes of the Highlands Preservation Act.