---
title: Cave-In-Rock, Illinois: Hideout of the Mason Gang and Harpe Brothers
author: Daniel Schwen
source: https://www.worldhistory.org/image/21442/cave-in-rock-illinois/
format: machine-readable-alternate
license: Creative Commons Attribution-ShareAlike (https://creativecommons.org/licenses/by-sa/4.0)
updated: 2025-12-12
---

# Cave-In-Rock, Illinois: Hideout of the Mason Gang and Harpe Brothers

_Authored by Daniel Schwen_

## Image File

[![Cave-In-Rock, Illinois: Hideout of the Mason Gang and Harpe Brothers](https://www.worldhistory.org/uploads/images/21442.jpeg)](https://www.worldhistory.org/uploads/images/21442.jpeg)

## Image Caption

The Cave-In-Rock on the Ohio River, Illinois, was the hideout of the Mason Gang, led by [Samuel](https://www.worldhistory.org/samuel/) Mason, who routinely robbed flatboats on the river. The [Harpe brothers](https://www.worldhistory.org/article/2862/harpe-brothers/), on the run from the [law](https://www.worldhistory.org/disambiguation/law/), joined the Mason Gang here but were expelled by the pirates for their senseless cruelty.

Photograph by Daniel Schwen, 2008.

## Cite This Work

### APA
Schwen, D. (2025, December 12). Cave-In-Rock, Illinois: Hideout of the Mason Gang and Harpe Brothers. *World History Encyclopedia*. <https://www.worldhistory.org/image/21442/cave-in-rock-illinois/>
### Chicago
Schwen, Daniel. "Cave-In-Rock, Illinois: Hideout of the Mason Gang and Harpe Brothers." *World History Encyclopedia*, December 12, 2025. <https://www.worldhistory.org/image/21442/cave-in-rock-illinois/>.
### MLA
Schwen, Daniel. "Cave-In-Rock, Illinois: Hideout of the Mason Gang and Harpe Brothers." *World History Encyclopedia*, 12 Dec 2025, <https://www.worldhistory.org/image/21442/cave-in-rock-illinois/>.

## License & Copyright

[Original image](https://commons.wikimedia.org/wiki/File:Cave-in-rock_IL.jpg) by [**Daniel Schwen**](https://commons.wikimedia.org/wiki/File:Cave-in-rock_IL.jpg). Submitted by [Joshua J. Mark](https://www.worldhistory.org/user/JPryst/ "User Page: Joshua J. Mark"), published on 12 December 2025. The copyright holder has published this content under the following license: [Creative Commons Attribution-ShareAlike](https://creativecommons.org/licenses/by-sa/4.0deed.en). This license lets others remix, tweak, and build upon a work even for commercial reasons, as long as they credit the author and license their new creations under the identical terms. When republishing on the web a hyperlink back to the original content source URL must be included. Please note that content linked from this page may have different licensing terms.