Washington was born in 1798 in Virginia. He was a son of Susan Monroe (née Grayson) Washington (1770–1822) and Lund Washington (1767–1853), the postmaster of Washington, D.C.[1] After his mother's death in 1822, his father married Sarah Johnson, a daughter of Capt. John Johnson.[2]
His father was named for his uncle, Lund Washington, who was the neighbor and distant cousin of President George Washington. His paternal grandparents were Robert Washington and Alice (née Strother) Washington.[3] His maternal grandparents were Mary Elizabeth (née Wagener) Grayson and the Rev. Spence Monroe Grayson,[4] brother of U.S. SenatorWilliam Grayson (through their mother, they were cousins of James Monroe).[5]
In 1822, Washington was married to Margaret MacPherson (1786–1874), a daughter of Gen. William MacPherson and Margaret Stout MacPherson. Margaret's younger brother, Joseph Stout MacPherson, was married to Peter's younger sister, Mary Elizabeth Washington.[3] Together, they were the parents of:[2]
Virginia Grayson Washington (1824–1869), who died unmarried.[2]
Julia Maria Washington (1827–1914), who married Dr. Caleb W. Hornor in 1859.[2]
William McPherson Washington (1828–1849), who died unmarried.[2]
Washington died in New York City on February 10, 1872. His funeral was held in Washington at the Church of the Epiphany and conducted by the Rev. Dr. Starkey.[8]