Francis Preston Blair Jr. was a United States Senator, a United States Congressman and a Union Major General during the Civil War. He represented Missouri in both the House of Representatives and the Senate, and was active in preventing the State of Missouri from being absorbed into the Confederacy at the beginning of the Civil War.

Montgomery Blair was an American politician and lawyer from Maryland. He served in the Lincoln administration cabinet as Postmaster-General from 1861 to 1864, during the Civil War. He was the son of Francis Preston Blair, elder brother of Francis Preston Blair Jr. and cousin of B. Gratz Brown.