USS Sangamon, an 1335-ton Passaic-class monitor built at Chester, Pennsylvania, was commissioned in February 1863. During most of 1863 she served in the James River, Virginia, taking part in offensive moves up that river in July and August. In early 1864, Sangamon was transferred to the blockade off Charleston, South Carolina, but returned to the James later in the year. In March and April 1865, she took part in operations to counter the threat of Confederate ironclads and to clear mines from the river. Following the end of the Civil War, Sangamon was placed out of commission at Philadelphia, Pennsylvania. Renamed Jason in June 1869, the monitor was apparently inactive from 1865 until 1898.

Jason recommissioned in May 1898 for Spanish-American War service. Stationed on Long Island, she provided the New York area with some degree of naval protection against the perceived threat of a raid by Spanish cruisers. Again laid up at Philadelphia after the end of the conflict, USS Jason was sold in April 1904.