The last Montana State Fair was held in Helena in 1932 . The 1935 Helena earthquake and several fires in the 1930s and 1940s destroyed several unspecified structures associated with the horse racing track . In the fall of 1937 , the three north stables and veterinarian 's cottage burned down . Horse racing ended during this time , and the track was abandoned except for the small section in front of the grandstand ( used as part of the automobile race track )
1935 Helena earthquake
1935 Helena earthquake
Montana State Fairgrounds Racetrack