Mills [13, pp. 96-1081 and Muth [17] have published simulation models of urban residential land use that are similar enough to warrant classifying them as one model type.' The purpose of this paper is to test that model and provide extensions to improve its ability to simulate real urban areas. In Section 1, we discuss the mathematical structure and solution technique of the model. In Section 2, we construct a composite urban area which serves as our benchmark for judging the model's accuracy. Section 3 contains a discussion of parameter values. A comparison of actual and simulated results is made in Section 4. In Section 5, we provide extensions, and in Section 6 we discuss the necessary additional parameter values. Section 7 contains a comparison of actual and simulated values for the extended model. We offer a sensitivity analysis of the extended model in Section 8. Finally, Section 9 contains a brief summary.