Ecological Site Descriptions

Montana rangeland is organized into five large Rangeland Resource Units: West, North, Central, South, and East. Each of the five large units is divided into more basic Rangeland Resource Units along Major Land Resource Area (MLRA) boundaries. Divisions are determined on factors such as precipitation (kind, timing, and amount), temperatures, plant functional groups (cool season grasses versus warm season grasses), etc.

More information and definitions regarding Major Land Resource Areas and Ecological Site Descriptions are available from the NRCS soil survey and rangeland management programs.

If you encounter any problems with the file provided on this page, please contact Technical Resources at 406-587-6822.

The following documents are available in Adobe Reader format.

Montana Ecological Site Key (PDF; 131 KB)
Montana Ecological Site Development Policy (PDF; 1.2 MB)

To access the ecological site descriptions for a basic Rangeland Resource Unit, select the appropriate spot on the map or skip to the text links below.

Montana Rangeland Resource Unit and MLRA Map

Montana Rangeland Resource Unit and MLRA List

West

• 43AW - Northern Rocky Mountains, West (MLRA 43A - Northern Rocky Mountains)
• 43BW - Central Rocky Mountains, West (MLRA 43B - Central Rocky Mountains)
• 44W - Northern Rocky Mountain Valleys, West (MLRA 44 - Northern Rocky Mountain Valleys)

North

• 43BN - Central Rocky Mountains, North (MLRA 43B - Central Rocky Mountains)
• 46N - Northern Rocky Mountain Foothills, North (MLRA 46 - Northern Rocky Mountain Foothills)
• 52N - Glaciated Plains, North (MLRA 52 - Brown Glaciated Plains)

Central

• 32C - Desertic Basins, Central (MLRA 32 - Northern Intermountain Desertic Basins)
• 43BC - Central Rocky Mountains, Central (MLRA 43B - Central Rocky Mountains)
• 44C - Northern Rocky Mountain Valleys, Central (MLRA 44 - Northern Rocky Mountain Valleys)
• 46C - Northern Rocky Mountain Foothills, Central (MLRA 46 - Northern Rocky Mountain Foothills)
• 52C - Glaciated Plains, Central (MLRA 52 - Brown Glaciated Plains)
• 58AC - Sedimentary Plains, Central (MLRA 58A - Northern Rolling High Plains, North Part)

South

• 43BS - Central Rocky Mountains, South (MLRA 43B - Central Rocky Mountains)
• 44S - Northern Rocky Mountain Valleys, South (MLRA 44 - Northern Rocky Mountain Valleys)
• 46S - Northern Rocky Mountain Foothills, South (MLRA 46 - Northern Rocky Mountain Foothills)

East

• 53AE - Glaciated Plains, East (MLRA 53A - Northern Dark Brown Glaciated Plains)
• 54E - Soft Shale Plains, East (MLRA 54 - Rolling Soft Shale Plains, North Part)
• 58AE - Sedimentary Plains, East (MLRA 58A - Northern Rolling High Plains, North Part)
• 60BE - Pierre Shale Plains, East (MLRA 60B - Pierre Shale Plains, North Part)

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Last Modified: 06/16/2005