This study found that area burned during the 30-year period, number of fires each year, and fire size followed a strong geographic pattern: Northern Intermountain > Southern Intermountain > Southern Rocky Mountain > Central Rocky Mountain. Area burned within piñon and juniper land cover types increased significantly during the 30-year period across the study area overall and for each geographic region, except the Southern Intermountain. Fire rotations were within reported historical ranges for sagebrush ecosystems and decreased over time. Also, fire number or fire size increased for the Southern Rocky Mountain and Southern Intermountain geographic regions. Across the study area, spatio-temporal patterns in fire regimes for piñon and juniper land cover types were similar to those for other land cover types. Careful monitoring of longer term trends in fire activity and the interacting effects of invasive annual grasses, bark beetles, and climate change is needed to access the dynamics of piñon and juniper land cover types and evaluate the efficacy of management treatments in piñon and juniper land cover types.