This lake was constructed in 1989. Named after the late R.C. Longmire who among others, saw the need for another water supply lake. With over 900 acres of surface water, one just needs to drive out to the lake to observe the scenic beauty of this lake. Although constructed primarily as a water supply lake it was envisioned that the recreational opportunities of this lake were endless. How right they were! Longmire Lake offers recreational opportunities such as fishing, boating, camping, hiking, bird watching, hunting, and swimming. Longmire Lake also has a pavilion for social functions and has modern bathroom facilities.

With the help of the Oklahoma Wildlife Department, Longmire Lake has been designated as a trophy bass lake. Since 1990 Florida bass have been stocked in this lake and is monitored by the ODWC on a semi-annual basis to help insure the lake's status as a trophy bass lake. Since the construction of Longmire lake it has become a favorite wintering habitat for bald eagles having as many as a dozen eagles at one time.