The next day, August 20, they laid out a town of 20 acres (81,000 m2) 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 448 feet (137 m) above sea level.

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.

At the time the commissioners platted Marion, he had a small crop of corn and wheat growing over what became the public square.

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.

[6] On May 29, 1982, one of the larger tornadoes in Illinois history, rated F4, hit the city of Marion and Williamson County.

The Shawnee Village apartment complex was destroyed, and the Marion Ford-Mercury dealership sustained heavy damage.

A memorial to the ten people who perished that day was later erected on the south side of Tower Square Plaza.

The Cost of Living Index estimates the relative price levels for consumer goods and services.

The largest sector in the Marion city, IL is Health Care and Social Assistance, employing 4,015 workers.

The sectors with the largest LQs in the region are Finance and Insurance (LQ = 2.33), Health Care and Social Assistance (1.50), and Accommodation and Food Services (1.49).

Sectors in the Marion city, IL with the highest average wages per worker are Utilities ($125,515), Mining, Quarrying, and Oil and Gas Extraction ($73,866), and Health Care and Social Assistance ($65,918).

The fastest growing sector in the region is expected to be Transportation and Warehousing with a +0.5% year-over-year rate of growth.

As of March 30, 2009, the largest employers located inside the city limits were as follows:[11] Other major nearby employers include: Downtown Marion is home to the Little Egypt Arts Gallery operated by the Little Egypt Arts Association as well as the Williamson County Historical Society museum and the Marion Carnegie Library.

After a 1997 fire destroyed the city's former civic center, the new facility was crafted using parts of the old Orpheum Theater building.

Built in the southwest corner of the downtown square, she was the flagship of a chain of vaudeville and moving picture theaters constructed to tap into the wealth generated by agriculture and mining in Southern Illinois.

The Orpheum Theatre sat over 900, and was ornately decorated in a mix of Renaissance and Neoclassical styles, complete with gold leaf, elaborate plasterwork, and a multicolored terra-cotta facade.

The mayor and the city council reconsidered their plan when they found that their citizenry was in favor of restoring the old theater for use by the community as a cultural and entertainment center.

Camping facilities in the city include the new Marion Campground & RV Park, located off of Exit 53 on the east side of the interstate.

[14] Major attractions that draw visitors to Marion include events at Marion Stadium (Mt Dew Park), events at Southern Illinois University-Carbondale, The Southern Illinois Roller Girls bouts at The Pavilion Events, approximately two dozen wineries within a 45-mile (72 km) radius of the city including those on the Shawnee Hills Wine Trail and the Southern Illinois Wine Trail, Crab Orchard National Wildlife Refuge adjacent to the city, Lake of Egypt immediately to the south and the Shawnee National Forest and various state parks that stretch along the Shawnee Hills from river to river.

Contour Airlines provides daily passenger flights to O'Hare International Airport in Chicago.

Local service from those lines is provided by the Crab Orchard and Egyptian Railroad headquartered in Marion.