Marshall is a city in and the county seat of Harrison County in the northeastern corner of the U.S. state of Texas. Marshall is a major cultural and educational center in East Texas and the tri-state area. At the 2010 census, the population of Marshall was about 23,523. Marshall was a political and production center of the Confederacy during the Civil War. Later it was a major railroad center of the T&P Railroad from the late 19th century until the mid-20th century.