William P. Mahoney (1838-1916) was the son of William Mahorney (died 1846) and Jane Patterson (c.1814-before 1909) of King George and Stafford Counties, Virginia. The younger William married Mary A. Riley (born c.1848). They resided at Chappawamsic Farm, formerly owned by George Mason, III (1690-1735). The house site is now part of the Quantico Marine Corps reservation. Hilldrup Transfer and Storage Company occupied part of the property. In 1881, William P. Mahoney was overseer of the road “leading from Chappawamsic Run to Stone’s Mill.” This roughly follows modern U. S. Route 1 southward to Garrisonville Road (Route 610).