Here, we characterize and compare rodent assemblages from crop fields and rangelands of the 4 Pampa districts included in Buenos Aires province, Argentina, to analyze the role of regional context, land use, and vegetation structure in determining the structure of rodent assemblages at the plot scale. Habitat generalist species (Calomys laucha and Mus musculus) tended to be more abundant in crop fields, whereas habitat specialists (Akodon azarae and Oxymycterus rufus) tended to be more abundant in rangelands. However, the degree of spatial segregation between habitat generalists and specialists and the associations between particular rodent species and land use differed among districts. The abundance of the dominant species (C. laucha and A. azarae) was positively associated with vegetation height. We also found a positive association between the abundance of the dominant species in a certain land use and the representation of that land use in the Pampa district, which suggests an effect of the regional context on local assemblages. Our results show that the structure of the rodent assemblage in a certain plot is the result of the interaction between the district the plot is in and the land use (and management) it is under. Future studies could shed light to the mechanisms behind the district effect observed in this study.