Camagüey Province occupied a large area of eastern Cuba and included some very productive sugar growing areas, particularly in the south and west, around the towns of Ciego de Avila and Florida. Mills here tended to be large and widely spaced with extensive standard gauge railway systems.
Camagüey province was split into two new provinces in 1976, Ciego de Avila and Camagüey. The old provincial structure was the basis of the mill numbering system and was widely understood in the industry and in railway enthusiast circles. It is used here for convenience. Camagüey mills were numbered in the 5xx series.