Joseph King Fenno Mansfield, American army officer.
Mansfield, Joseph King Fenno was born on December 22, 1803 in New Haven, Connecticut, United States. Son of Henry and Mary (Fenno) Mansfield.
Graduated from the United States Military Academy, 1822.
Commissioned Second lieutenant Corps Engineers, United States Army, 1822, First lieutenant, 1832, captain, 1838. Served in Mexican War, 1846-1848. Chief engineer, brevetted major, then lieutenant colonel, colonel.
Captain in construction coast defenses until 1853. Colonel, inspector general, 1853. Commissioned brigadier general United States Army, assigned to command Department Washington (District of Columbia), including capitol and surrounding territory, 1861.
Commissioned major general United States Volunteers, 1862.
Married Louise Mather, September 25, 1838, 4 children.