Cave-in-Rock State Park
|Cave-In-Rock State Park|
|U.S. state of Illinois showing the location of Cave-In-Rock State Park|
|Location||Hardin County, Illinois, USA|
|Nearest city||Elizabethtown, Illinois|
|Area||204 acres (83 ha)|
|Location:||0.5 mi N of the town of Cave-In-Rock, Cave-In-Rock, Illinois|
|Area:||less than one acre|
|Architectural style:||Other, natural cave|
|MPS:||Caught in the Middle: The Civil War on the Lower Ohio River MPS|
|Added to NRHP:||August 6, 1998|
Cave-In-Rock State Park is an Illinois state park on 204 acres (83 ha) in Hardin County, Illinois in the United States. The state park contains the historic Cave-in-Rock, a landmark of the Ohio River. It is maintained by the Illinois Department of Natural Resources (IDNR).
The Cave-in-Rock was worn into the limestone bluffs of the Ohio by river floods, especially during the meltoff following the Wisconsin ice age. It is not a karstland cavern like Mammoth Cave in nearby Kentucky; it is an obvious, 55-foot (17 m) wide tunnel leading a long distance into the bluff.
Cave-in-Rock was known and used for thousands of years by the Native Americans. It was mapped and named in 1729 by the French explorer de Lery, who named it the caverne dans le Roc. This name, translated directly into English, is the name the cave bears to this day.
During the 1790s and first decade of the 19th century, Cave-in-Rock reached the height of its notoriety. Flatboats carrying farm produce from Kentucky, Ohio, and southern Indiana began to float down the Ohio River towards the marketplace in New Orleans. As a known Ohio River landmark, the cave was a landmark of this dangerous journey. From approximately 1797 until 1799, the cave was a hideout for a notorious gang of bandits, headed by Gregory Mason, that preyed upon the lawless river commerce.
Later in the 19th century, Cave-in-Rock was tamed by settlers who formed the river town of Cave-in-Rock, Illinois near the cave. The town survives to this day. It became the site of a river ferry, adjacent to the state park, that crosses the Ohio River from Illinois Route 1 to Kentucky Route 91.
State park 
With the inauguration of steamboat traffic on the Ohio River in the 1810s, travelers such as artist Karl Bodmer bought tickets to steam up and down the river, and Cave-in-Rock has been a recognized landmark of river tourism ever since. In 1929, the state of Illinois acquired 64.5 acres of land, including the cave. Other small parcels of land were acquired later to form the current park. The state park, which stretches from the river's edge to the top of the adjacent 60-foot (18 m) tall bluff, is maintained by IDNR for Ohio River access, camping, and hiking, including hikes to the historic cave.
- "Cave-in-Rock - State Park". Illinois Department of Natural Resources. Retrieved 2007-04-03.
- USGS. "United States Geological Survey Topographic Map, USGS CAVE-IN-ROCK (KY) Quad". TopoQuest. Retrieved 2008-06-30.