The region in Montana that starts in Columbus and stretches west to Butte. It goes north into Townsend and south near the Idaho and Wyoming borders and Yellowstone National Park. The people here are like a hybrid between Eastern and Western Montana, and Butte is included even though it is west of the divde. Bozeman is located here, but due to its uniqueness is in a class by itself as is Helena, which is a mixture of the three regions.
Southwest Montana is often not thought of as a region, but due to it being a mix of Western and Eastern Montana, it deserves its own classification.