Samuel P. Cox (December 16, 1828 – August 21, 1913) was a businessman and farmer who is best remembered as the commander of the Union troops that killed "Bloody Bill" Anderson in the Battle of Albany in the American Civil War.
An alleged attempt to assassinate Cox in 1869 in reprisal for the killing marked the first time that Frank James and Jesse James were publicly identified as outlaws.
Cox was born in Williamsburg, Kentucky. He moved with his parents to Daviess County, Missouri in 1839. He joined the Army during the Mexican-American War in 1847. After the war he returned to Gallatin, Missouri and briefly settled in Grass Valley, Nevada and Oroville, California (1854-1856) before returning to Daviess County in 1857 where he was briefly a deputy sheriff. He worked for Russell, Majors and Waddell as a wagon master during the Utah War in 1858-59.
In 1861 Cox joined the Missouri Militia with the rank of major. During this time he was elected in absentia circuit clerk of Daviess County in 1862. He resigned in 1863, citing ill health, and returned to Gallatin.
In 1864 he returned to the Missouri Militia, this time as a lieutenant colonel of the Thirty-third Regiment of Missouri State Militia.
On September 27, 1864, Anderson's troops seeking to assist Price's Raid, a Confederate attempt to retake Missouri in the Civil War, killed more than 100 in the Centralia Massacre. Union soldiers were scalped, mutilated, and shot at point-blank range while unarmed, prompting an all-out effort to pursue Anderson. Among Anderson's men at Centralia were reported to be Frank James and Jesse James, although their notoriety had not been established at that point.