England's King Charles I granted the entire Potomac River to Maryland in 1632. Four centuries later Maryland, Virginia, and the District of Columbia were still arguing over their mutual boundary.Alexander's Island was one controversial site. It was known for its "bogs and swamps and frogs." At low tide the island was attached to - and claimed by - Virginia. At high tide the Potomac River encircled it, making it part of the District of Columbia.Tensions over Alexander's Island exploded in 1904. A group of enraged men carrying axes and sledgehammers raided the Alexander Island Race Track in an attempt to close it. The District of Columbia did not permit race track betting, while Virginia did.In 1915 the Army Corps of Engineers began dredging the Potomac River. In the process they completely removed the swampy landmass that was Alexander's Island. In its place they created the Boundary Channel, which runs beneath this footbridge, and Columbia Island, which is visible across the channel from you.In 1934 Congress determined that, while Alexander's Island had once definitely been part of Virginia, its destruction shifted the shoreline of the Potomac River. The Boundary Channel became the new official border for Virginia, and the man-made Columbia Island was unquestionably part of Washington, D.C.Captions:The
Boundary Channel and Columbia Island on a World War II era map.A surveyor's map from 1794 shows the narrow bog that attached Alexander's Island to the Virginia shoreline.