Trego is an unincorporated community and census-designated place (CDP) in Lincoln County, Montana, United States. As of the 2010 census it had a population of 541. It is southeast of Eureka.
Trego was originally settled by Octave Fortine. It was a station on the Great Northern Railway line. The first post office was established in 1911. Trego now has a pub and general store established in 2019. Trego also has an elementary school that has been around since the 1900s. Trego used to be a big logging area, and a lot of logging is still happening in the Trego area.
Trego is in northeastern Lincoln County and occupies a large portion of the valley of Fortine Creek and surrounding countryside. U.S. Route 93 runs along the northeast edge of the CDP, about 2.5 miles (4.0 km) northeast of the original railroad-station community of Trego, while the CDP extends southwest from the rail station up Fortine Creek for 10 miles (16 km).