1935 - PIMA COUNTY FAIRGROUNDS
Pima County Fairgrounds opened for speedway racing in 1935, on the big one mile dirt oval horse track. Midget racing was the feature of the program.
As was the case with all other tracks around the world, World War 2 would put an end to the speedway in 1941.
1946 - PIMA COUNTY FAIRGROUNDS
With the end of World War 2 and the Motorsport ban being lifted, Pima opened once again but as a 1/2 mile track, running Stock Cars on a regular basis.
1955 - PIMA COUNTY FAIRGROUNDS
It was in 1955 that speedway racing ceased at the Fairgrounds. It is unknown why the board made this decission.
1970 - PIMA COUNTY FAIRGROUNDS
In 1970 the Fair Board changed its mind and re introduced Stock and Modified racing events at the venue, sadly this only lasted till the end of the 1972 season when speedway racing once again was dumped.