Spatial allocation generally involves the aggregation of spatial units into larger groups according to specified criteria. This paper describes a generalized method of formulating integer programming models for spatial allocation (IPSA). To do so, IPSA are decomposed into elementary forms which can then be recomposed for particular applications in a clear and consistent manner. The major implication of this paper is that the prescriptive capabilities of geographic information systems (GISs) can continue to benefit from future advances in mathematical programming techniques.