Baker is a city in and the county seat of Fallon County, Montana, United States. The population was 1,741 at the 2010 census.
It was named after A.G. Baker, an engineer with the Chicago, Milwaukee, St. Paul and Pacific Railroad.
Baker was built along the transcontinental rail line of the Milwaukee Road near where the railroad created a lake to supply water to its steam locomotives. The city was known as Lorraine for a brief time before being renamed in honor of Milwaukee Road engineer A.G. Baker. A successful Milwaukee Land Company campaign to attract homesteaders to the area allowed the city to grow and serve a large community of dryland farmers. Additional growth occurred following the 1912 discovery of oil and natural gas deposits nearby.