Marshall County was named in 1842 for John Marshall, 1755-1835, Chief Justice of the United States from 1801 to 1835 and called the principal founder of judicial review and of the American system of constitutional law. The area was first settled about the time of the Jackson Purchase in 1818. The first church west of the Tennessee River in Kentucky was started by Rev. H. Darnall, a Baptist, in 1819 on Soldier Creek. The county was formed from Calloway County.