Cumberland Mountain State Park is a state park in Cumberland County, Tennessee, in the southeastern United States. The park consists of 1,720 acres situated around Byrd Lake, a man-made lake created by the impoundment of Byrd Creek in the 1930s. The park is set amidst an environmental microcosm of the Cumberland Plateau and provides n…Cumberland Mountain State Park is a state park in Cumberland County, Tennessee, in the southeastern United States. The park consists of 1,720 acres situated around Byrd Lake, a man-made lake created by the impoundment of Byrd Creek in the 1930s. The park is set amidst an environmental microcosm of the Cumberland Plateau and provides numerous recreational activities, including an 18-hole Bear Trace golf course.