Big River covers a total area of 8319 acres. The area is composed of mainly forest land (evergreens 4374 acres, deciduous 1781 acres), wetlands (1288 acres), agricultural lands (233 acres), and other areas (gravel, residential, etc. 407 acres). Major rivers or streams in the area are Big River, Nooseneck River, Congdon River, and Carr River.

The AllTrails website has descriptions and maps of many trails in the Big River Management Area.