 This left in doubt the exact position of the District's border with Virginia.In "Morris v. United States", 174 U.S. 196 (1899), the Supreme Court of the United States held that land built in the Potomac River not only belonged to the District of Columbia but to the federal government (contrary to the claims of private landowners, who believed the property belonged to them).In "Maryland v. West Virginia", 217 U. S. 1 (1910), the U.S. Supreme Court again affirmed that Maryland's southern border extended to the low-water mark on the far side of the Potomac River.