Fort Kaskaskia State Historic Site preserves the time-worn earthen remains of Fort Kaskaskia, constructed by the French ca. 1759 to defend the town of Kaskaskia. Founded in 1703, the town was for more than a century the regions principal commercial center, also serving from 1818 to 1820 as the first capital of Illinois. The small fort, containing only a three-room barrack and a kitchen, was apparently never fully completed. The fort was periodically occupied by French or U.S. troops until 1807 and sheltered local settlers during Indian scares rising from the War of 1812.

Todays historic site consists of four major sections the remains of Fort Kaskaskia, Garrison Hill Cemetery, the Mississippi River overlook and picnic area, and a large campground. The remnants of Fort Kaskaskia include long earthworks forming a rough square, with bastions at the corners. Garrison Hill Cemetery was established in 1891 by the General Assembly for the remains of early settlers whose graves were threatened by the flooding of Kaskaskia. A large monument erected in 1892 and commemorating the early settlers is also located in the cemetery. The grassy bluff overlooking the Mississippi provides a sweeping view of the river and Kaskaskia Island. Panels describe the rich history of Kaskaskia village, including its destruction in the 1880s-1890s by the Mississippi River. The overlook and nearby day-use area include picnic shelters with tables and grills. A campground includes tent-camping sites and thirty-two electrified sites. Playground equipment is located near each end of the day-use area. A footpath leads to the Pierre Menard Home State Historic Site, located at the bottom of the bluff.

The campground is open 24-7 for camping with quiet hours from 10pm to 7am. There is normally a host on duty on the weekends May - Oct but there is also an iron host self-check in station. Campsites are currently walk in only on a first come first serve basis.