This paper reviews the use of a documentary source from the 18th century, the Ensenada Cadastre, as a tool of geohistorical study. This documentary source provides a way of furthering knowledge about the economy of each town in the crown of Castile. The town of Cubillas de Santa Marta, in the province of Valladolid, has been used as an example here. Thanks to this analysis of the cadastral documentation, it has been possible to analyse the agricultural activity and the distribution of crops, to determine the resulting landscape, and thus to be able to compare that with its current state. [ABSTRACT FROM AUTHOR]