Colonial Beach, a small incorporated town in Westmoreland County located on the Potomac River waterfront, developed as a popular tourist spot for the people of the Washington, D.C. area in the nineteenth and twentieth centuries. It offered a beach, swimming, and gambling. The gambling facilities were built on piers extending into the Potomac River to ensure they were inside Maryland, as the state border runs along the southern low tide line of the Potomac River. With the end of gambling, and improved access to competing Maryland and Delaware ocean beaches, Colonial Beach declined in popularity as a tourist destination. It and the rest of the Northern Neck still continue to attract dedicated outdoor enthusiasts for fishing and boating.