Roxbury High School primarily serves the six communities that make up Roxbury Township in Morris County, NJ:
Ledgewood, Kenvil, Landing, Succasunna, Port Morris and Lower Berkshire Valley. Mount Arlington students also attend Roxbury HS to this day. Over the years many other Municipalities without a public High School have sent their students to Roxbury. The 1958 Yearbook also  records seniors from Chester, Jefferson Township, Flanders, Budd Lake, Wharton and a few others. Not all students from those towns attended Roxbury. With housing growth, in 1958 Chester Township & Borough, Washington Township, Mendham and Mount Olive formed a regional high school district and opened West Morris Central High School for their freshman students.