The Jarrot Mansion

The Jarrot Mansion was added to the National Register of Historic Places in 1974.[1] A predecessor agency to the IHPA acquired the house in 1980. The house was elevated to the rank of a National Historic Landmark in 2001.[1] As of 2008, the Mansion is a largely inactive historic site. The IHPA keeps it closed to the public except for periodic seasonal open-house festivals.

The Jarrot Mansion is located less than one-half mile from the Cahokia Courthouse State Historic Site, where Jarrot served as judge of St. Clair County.

Holy Family Log Church

The Church of the Holy Family is a Roman Catholic church located in the St. Clair County, Illinois city of Cahokia. The Log Church, built in 1799 and replacing a similar church built in 1699, is the oldest church completely west of the Alleghany Mountains. (A Methodist church in Union, West Virginia, built in 1785 is west of highest ranges of the Alleghany Mountains.) Constructed of black walnut timbers in the traditional French Colonial ""poteaux-sur-solle"" (post-on-sill) vertical-log construction style, the Log Church is only one of five built in this style that still exist in North America. The church was declared a National Historic Landmark and added to the National Register of Historic Places in 1970. The building is located on First Street in Cahokia.[1]

Holy Family parish is the oldest continuously active Catholic Parish in the United States, having been founded in 1699 by Canadian missionaries. Roman Catholic Services are still conducted in the church[3]