According to the
United States Census Bureau, the town has a total area of , of which is land and is water. The town is divided by the
Stillwater River, a branch of the
Penobscot River. It occupies the southern part of
Marsh Island, surrounded by the Penobscot and the Stillwater rivers, where the University of Maine campus is located. Orono also occupies
Ayers Island, the site of a demolished paper mill, Browns Island, a small protected natural area upstream of the
Orono Dam, and part of Moose Island on
Pushaw Lake. The remainder of the town is on the mainland. The Orono Dam impounds the Stillwater River at its confluence with the Penobscot River near downtown Orono. The seasonal Johnny Mack Brook flows through the town into the Penobscot River. Orono is located along
U.S. Route 2 (Route 15 in the now-obsolete
New England road marking system). Orono marks the eastern terminus of
Maine State Route 16, which intersects with U.S. Route 2 in Monument Square in downtown. Orono is located at milepost 145 of the
Maine Central Railroad, the railroad bridge in town was built in 1885. and
WRCC (average extremes) }} ==Conservation==