[2] He received promotion to brevet lieutenant colonel on March 15, 1842, for his services during the Second Seminole War in Florida.

[2] He received brevet promotion to colonel for gallantry in General Zachary Taylor's Rio Grande campaign.

On November 10, 1851, Belknap died of typhoid dysentery while near Fort Washita in then Choctaw nation Indian Territory while scouting locations for a military post to protect native lines, California-bound emigrants and settlers en route from the Brazos River to Fort Washita, a hostile Indian Territory.

His son, William Worth had his remains moved to Iowa from outpost Fort Belknap in Young county Texas near Newcastle, according to TSHA [3] He was buried at Fort Washita, and later reinterred at Oakland Cemetery in Keokuk, Iowa.

[5] They were the parents of four children, including Anna Mary (1821–1893), Clara Belknap Wolcott (1824–1906), William Worth (1829–1890) and Frederick Augustus (1832–1832).