Unofficial nickname. Refers to the stateâ€™s wide open spaces. A relatively recent nickname, "Big Sky Country" originated with a 1962 promotion of the Montana State Highway Department. It is a reference to the unobstructed skyline in the state. The name came from a book by Alfred Bertram Guthrie Jr., Big Sky. Mr. Guthrie gave the Highway Department permission to use the name and Montana has been "Big Sky Country" ever since.