Butterfield Overland Trail Study Act - Directs the Secretary of the Interior to conduct a resource study along the "Ox-Bow Route" of the Butterfield Overland Trail in the states of Missouri, Tennessee, Arkansas, Oklahoma, Texas, New Mexico, Arizona, and California. Requires that the study evaluate a range of alternatives for protecting and interpreting the resources of the trail area, including alternatives for potential addition of such area to the National Trails System.