From circa 1827, Garret Cotter inhabited the Cotter Valley and the Cotter River received its name by association. Cotter was born in 1802 in County Cork. He had been a ploughman and was transported in 1822 on the Mangles. He received his ticket of leave in 1843 and was working on Lake George but became involved in a dispute between his employer and his employer's neighbour and was banished to live beyond the limits of location; in this case west of the Murrumbidgee River. In 1841 he married Anne Russell. After five years of living in the Cotter Valley, he was conditionally pardoned in 1847 and moved to Michelago. He was listed as a squatter of Michelago in 1872. He and Anne had nine children. Garrett died in 1886 and Anne in 1897. Both are buried at Michelago.
- Mayberry, Peter. "Garret Cotter". Irish Convicts to New South Wales 1791-1831. Retrieved 2006-11-30.
- Uebel, Lesley (2002). "PJ Mangles 1822: Convicts landed from "Mangles" assigned to at Windsor (Transcribed from Reel 6009; 4/3506 p.432)". AUS-PT-JACKSON-CONVICTS-L Archives. RootsWeb. Retrieved 2006-11-30.
- "State Records NSW". State Records Authority of New South Wales. 1843. Retrieved 2007-07-04.
- "Chronology of the ACT". Discover our Territory. Canberra & District Historical Society. Retrieved 2006-11-30.
- "Greville's Post Office Directory - 1872 (letter C)". 1872. Archived from the original on 2006-10-04. Retrieved 2006-11-30.
- Exploring the ACT and Southeast New South Wales, J. Kay McDonald, Kangaroo Press, Sydney, 1985, p49 ISBN 0-86417-049-1