Sumiton is a city in Jefferson and Walker counties in the State of Alabama. It incorporated in 1952. At the 2010 census the population was 2,520…Sumiton is a city in Jefferson and Walker counties in the State of Alabama. It incorporated in 1952. At the 2010 census the population was 2,520, down from 2,665 in 2000. According to the U.S. Census Bureau, the city has a total area of 5.3 square miles, all land.