The impact of non-resident travel has been researched by the Institute for Tourism and Recreation Research (ITRR) at the University of Montana since 1987. Additionally, the U.S. Travel Association measures the impact of tourism in each state, and the National Park Service measures visitor statistics and the economic impact of Yellowstone National Park and Glacier National Park on local communities.
In 2021, Montana’s over 12.5 million non-resident visitors: