Ornbaun is a former settlement in Mendocino County, California. It was located on Rancheria Creek just east of Ornbaun Valley.
The Ornbaun post office opened in 1897, moved in 1907 and again in 1908, and closed in 1926. The name honors John S. Ornbaun, an early settler and rancher.
- ^ a b c d Durham, David L. (1998). California's Geographic Names: A Gazetteer of Historic and Modern Names of the State. Clovis, Calif.: Word Dancer Press. p. 117. ISBN 1-884995-14-4.