Location:

To reach the benchmarks from the Portsmouth traffic circle (Junction of I-95 and US-1 Bypass) proceed south on US 1 Bypass for 2.6 km (1.6 mi) where US 1 Bypass joins US 1, continue south on US 1 for 0.8 km (0.5 mi) and turn east (left) onto Elwin Road, go 2.3 km (1.4 mi) on Elwin Road to the intersection of route 1-A (Sagemore Road) and turn NW (left), proceed on route 1-A for 0.7 km (0.4 mi) to the intersection of route 1-A and Route 1-B (Wentworth Road), turn NE (right) and proceed 4.2 km (2.6 mi) to where Route 1-B turns sharp left onto Main Street, (there is a sign for the Coast Guard and Fort Constitution) stay on Wentworth Road (straight), continue 0.5 km (0.3 mi) to the access road for the Coast Guard Base and the pier, turn right and proceed 0.24 km (0.1 mi) to the gate, after passing through the gate, follow the parking lot NE for .08 km (0.05 mi), turn left between two buildings to the boathouse. The tide gage is located on the SW corner of the boathouse and the benchmarks are in the immediate area.