Sugarloaf Township, St. Clair County, Illinois

Dupo is a village in St. Clair County, Illinois, United States. The population was 4,138 at the 2010 census, an increase from 3,933 in 2000. The village was settled in about 1750 and was incorporated in 1907. Its modern name, adopted in the early 20th century, is shortened from Prairie du Pont ("Bridge Prairie").

The Lunsford-Pulcher Archeological Site is a prehistoric archaeological site in rural Monroe and St. Clair counties in Illinois. The site was the location of a Middle Mississippian village which was probably a satellite community of Cahokia. Several pyramidal burial mounds are included in the site. Archaeological excavations at the site have also discovered the remains of houses and garden beds, making the site one of the few Mississippian villages at which garden beds have been found. The site has been known to European settlers since early settlement of the area in the late 18th century; despite being used for farmland, the site remains in good condition.The site was added to the National Register of Historic Places on July 23, 1973.

Gibault Catholic High School is a private, Roman Catholic high school in Waterloo, Illinois. It is part of the Roman Catholic Diocese of Belleville.

The Pierre Martin House (or Martin–Boismenue House) is a single-family French Colonial House and historic site in East Carondelet, Illinois about 1.5 miles (2.4 km) East of the Mississippi River. The house, built circa 1790, is owned by the Illinois Historic Preservation Agency. and located at the intersection of First Street and Old Route 3 in North Dupo.

North Dupo is an unincorporated community in Sugarloaf Township, St. Clair County, Illinois, United States. North Dupo is located along Illinois Route 3 south of Cahokia and north of Dupo, bordering both villages. The Pierre Martin House, which is listed on the National Register of Historic Places, is located in North Dupo.

East Carondelet is a village in St. Clair County, Illinois, United States. The population was 499 as of the 2010 census.

Columbia is a city mainly in Monroe County with a small portion in St. Clair County in the U.S. state of Illinois, about 12 miles (19 km) south of St. Louis, Missouri. The population was 10,999 at the 2020 census.

The Gundlach-Grosse House is a historic house located at 625 N. Main St. in Columbia, Illinois. The Greek Revival house was built in 1857 for German immigrants John and Philip Peter Gundlach. The brothers ran a local brewery which remained in their family for four generations, and John Gundlach served as Columbia's mayor for four years. The house is a 1 ½-story brick building; its corbeled brick frieze is representative of the decorative brickwork commonly designed by German immigrant builders. The entrance to the house features a classical pediment supported by Ionic columns and cast iron pilasters. Two windows with broken scroll pedimented lintels are situated on each side of the door. The house's gable roof features three gabled dormers on the front and back sides.The house was added to the National Register of Historic Places on December 18, 1978.

Cahokia Heights is a city in St. Clair County, Illinois, United States. It was founded on May 6, 2021, by the merger of the villages of Cahokia and Alorton and the city of Centreville. On May 6, 2021, Curtis McCall Sr. was sworn in as the city's first mayor, having run unopposed.

Imbs (also known as Imbs Station) is an unincorporated community in Stookey Township, St. Clair County, Illinois, United States. Imbs is 4.5 miles (7.2 km) southeast of Cahokia.

Columbia High School is a public high school in Columbia, Illinois. It is part of Columbia Community Unit School District 4.

The Nicholas Jarrot Mansion is a historic house at 124 East First Street in Cahokia Heights, Illinois and is operated as an inactive historic site by the Illinois Historic Preservation Agency (IHPA). It is a State Historic Site, is listed on the National Register of Historic Places, and became a National Historic Landmark in 2001. Built in 1807–1810 for the son of French colonists, it is an extremely rare example of Federal architecture in the upper Mississippi River valley.