Cornelius Gilliam (April 13, 1798 – March 24, 1848) was a pioneer of the U.S. state of Oregon who was best known as the commander of the volunteer forces against the Cayuse in the Cayuse War. A native of North Carolina, he served in the Black Hawk War and Seminole Wars before settling in Missouri. There he served in the militia against the Mormons, was a county sheriff, and a member of the Missouri State Senate before immigrating to the Oregon Country.