The Warren sub-region is in the southwest corner of Western Australia and forms part of the South West NRM region. It encompasses the catchments of the Donnelly, Warren, Gardner, Shannon, Weld and Deep River systems as well as the Lake Muir Byenup system.

The whole of the Shire of Manjimup, as well as small portions of the Shires of Boyup Brook, Kojonup, Nannup, Cranbrook and Bridgetown-Greenbushes lie within the Warren sub-region. The Shire of Manjimup covers an area of 7028 km2.  The population of the Shire, which includes four towns and five settlements, is approximately 10,000.

Department of Parks and Wildlife (DPaW) estate accounts for approximately 80% of the Manjimup Shire lands; the remaining 20% is ratable land and has generally been cleared for agriculture and horticulture.

A small proportion of land is used for residential or semi-rural purposes.

The key industries for the region are agriculture (viticulture, orchards, aquaculture, horticulture) government services, forestry and tourism.

Key land uses include forestry, agriculture, horticulture, recreation and conservation.

By far the greatest proportion of the Warren sub-region is made up of the Warren Denmark Southland Soil Landscape Zone; however it also includes a small part of the Scott Coastal Zone and the Southern Zone of Rejuvenated Drainage to the west and to the north-east respectively.

The Warren sub-region enjoys a Mediterranean climate featuring dry, hot summers and cool winters.  Most of the annual rainfall occurs between the months of May and September each year.  Average annual rainfall across the sub-region ranges from approximately 530 mm at Kojonup to over 1200 mm at Pemberton.