33 C.F.R. § 80.125
Marblehead Neck, MA to Nahant, MA
The 72 COLREGS apply on the harbors, bays, and inlets on the east coast of Massachusetts from Marblehead Neck to the easternmost tower at Nahant, charted in approximate position latitude 42°25.4′ N., longitude 70°54.6′ W.