Fort Mountain" after observing it through his telescope thirteen miles away. The laccolith or butte was formed from magma pushing through previous layers of lava. The process makes a blister on the earth. According to Joseph Mussulman there are more than 2,000 geologic features in the US known as buttes.
Square Butte was one of Charlie Russell's favorite laccoliths. If you look through some of his paintings you will see Square Butte in the background. Look at his painting titled " Charles M. Russell and his Friends" 1922.