The Plymouth-Norfolk county line divides Black Rock Beach. Norfolk County is on the east side of the beach and Plymouth County is on the northwest side. If you carefully keep your bird records by county, be aware of the location of the county line and use the appropriate eBird hotspots when you submit checklists.

Black Rock Beach is named after the large black rocks scattered along the shore. The beach is popular for swimming, fishing, kayaking and surfing. The water is clear and cold, and the waves are moderate to strong. The beach is a scenic spot for hiking, picnicking, and birdwatching. The beach is open year-round, but parking is limited and there is no lifeguard on duty. Visitors should be aware of the potential hazards of rip currents, sharp rocks, and poison ivy.

Black Rock Beach is a short drive down the coastline from Sandy Beach and has 150 feet of shoreline in Cohasset.