Large tracts of land across the western United States have been managed over the last century in an effort to increase forage production, reduce the risk of wildland fires, and/or restore ecosystem structure and function. Yet documentation of this land-treatment history is lacking. With the use of data collected from Bureau of Land Management (BLM) field offices across the Colorado Plateau, we quantified the number, spatial extent, and implementation cost of tree-reduction and seeding treatments done in piñon (Pinus edulis)–juniper (Juniperus osteosperma, Juniperus monophylla, Juniperus scopulorum) woodlands between 1950 and 2003. Over 247 000 hectares of land were treated, corresponding to 6.6% of the piñon–juniper vegetation type within BLM-owned lands. Tree-reduction treatments involving chaining, bulldozing, or cabling were most prevalent between the 1950s and 1970s, with over 163 000 ha of land treated with these methods. Prescribed burning became increasingly prevalent in the 1980s, with over 43 000 ha burned. In more recent years, hydroaxe treatments have become common (4 400 ha treated), but to a much lesser extent than prescribed burns. Over 60% of these tree-reduction treatments were done in conjunction with revegetation or seeding treatments. Implementation costs of these tree-reduction treatments were over $26.7 million, with the hydroaxe treatment having nearly three times the cost of implementation than all other tree-reduction treatments. The spatial extent of these tree-reduction treatments and associated implementation costs highlight the importance of research examining the efficacy of these treatments and the potential legacy effects. The land-use history reported in this study and the accompanying freely accessible on-line database is a useful tool to guide research and management objectives and methodology.