Marion is a city in Williamson and Johnson Counties, Illinois, United States, and is the county seat of Williamson County. The population was 16,855 at the 2020 census. It is part of a dispersed urban area that developed out of the early 20th-century coal fields. Today Marion serves as the largest retail trade center in Southern Illinois with its central location along Interstate 57 and Illinois Route 13. It was dubbed the “Hub of the Universe” by former mayor Robert L. Butler. The city is part of the Marion-Herrin Micropolitan Area and is a part of the Carbondale-Marion-Herrin, Illinois Combined Statistical Area with 123,272 residents, the sixth most populous Combined statistical area in Illinois. History Following the creation of Williamson County out of the south half of Franklin County by the Illinois General Assembly, three commissioners appointed by the lawmakers met at Bainbridge, Illinois, on August 19, 1839, for the purpose of locating a new county seat as close to the center of the county as possible. The next day, August 20, they laid out a town of with a public square about one-quarter of a mile east of the county's center, but a point on top of a slight hill of above sea level. The site sat in a small open grassland known as Poor Prairie. For a name, they chose Marion to honor American Revolutionary War hero Gen. Francis "Swamp Fox" Marion. William and Bethany Benson had entered the quarter-quarter section of land that contained the future site of Marion just the previous year on September 8, 1838. He had lived in the county at least since 1817, and was the first settler to enter land in Poor Prairie. At the time the commissioners platted Marion, he had a small crop of corn and wheat growing over what became the public square. The Williamson County Court organized in Marion on October 7, 1839, at the Benson log cabin. Overflow crowds had to use pumpkins for stools. The federal government established a post office at Marion on January 30, 1840, and the legislature incorporated the community as a city on February 24, 1841. 1982 tornado On May 29, 1982, one of the larger tornadoes in Illinois history, rated F4, hit the city of Marion and Williamson County. Ten people died and 200 people were injured after this tornado ripped across a stretch. The Shawnee Village apartment complex was destroyed,