The hamlet of Calcium is in the southern part of the CDP, east of U.S. Route 11, while Sanfords Four Corners is in the central part of the CDP along New York State Route 342 east of US-11. Route 11 leads southwest into Watertown, the Jefferson county seat, and northeast to Gouverneur. Route 342 leads east along the south edge of Fort Drum to Black River and west to Interstate 81. Interstate 781 runs through the northern part of the Calcium CDP, connecting to the east with Iraqi Freedom Drive into Fort Drum and leading west to I-81.