Whitlash is an unincorporated community in northwestern Liberty County, Montana, United States, about five miles south of the province of Alberta across the Canada–US border. Whitlash has a post office and an elementary school that provides educational services in grades prekindergarten through 8. The community is accessible only by unpaved road. The Whitlash Border Crossing is about five miles to the north. As of 2014, Whitlash, with the zip code of 59545, had a population of 35 people.