Disturbances related to the impact of horses on trails in Rocky Mountain National Park vary across the landscape. Geomorphic monitoring of permanent sites suggests that horse traffic is not the single, dominant process active on trails, nor is degredation always a direct result of horse use. Instead, amounts and rates of change are a function of geomorphic and biologic characteristics of the terrain interacting with horse traffic of varying degrees. The most influential landscape factors governing trail deteriortion, rockiness, stoniness, vegetation, and drainage. - from Author