Harlowton is a city in and the county seat of Wheatland County, Montana, United States. The population was 997 at the 2010 census. The city was once the eastern terminus of electric operations (1914–74) of the Milwaukee Road railroad's "Pacific Extension" route, which went all the way to Avery, Idaho. Here, steam or diesel locomotives were changed or hooked up to electric locomotives. Harlowton was founded in 1900 as a station stop on the Montana Railroad, a predecessor to the Milwaukee, and was named for Richard A.