- Home: https://sourceforge.net/projects/pio/, http://pio.sourceforge.net/
- Inspiration: Settlers of Catan
- State: mature
- Download: https://sourceforge.net/projects/pio/files
- Keyword: board, strategy
- Code repository: https://svn.code.sf.net/p/pio/code (svn active)
- Code language: C
- Code license: GPL-2.0
- Developer: Andy Heroff, Bas Wijnen, Brian Wellington, Dave Cole, David Fallon, dirtside, Hal Eisen, Jeff Breidenbach, Kevin Eustice, Matt McClanahan, Matt Waggoner, Matt Zagrabelny, Micah Bunting, rclobus, RodrigoEspiga, Roman Hodek, Steve Langasek, Yevgeny Gurevich
Emulation of the board game The Settlers of Catan, which can be played over the internet.