Archival source materials and colonial period maps have been employed to reconstruct the settlement pattern characteristic of the chinampa districts of the Aztec capital, Tenochtitlan. The evidence includes detailed descriptions of a number of individual residential sites and chinampa holdings, which can be drawn to scale on street maps of the modern city. Genealogies and census data have been employed to determine the average size and social composition of typical urban households. Rough estimates of the economic value of urban chinampa holdings in relation to individual households, and to the urban population as a whole, indicate much higher levels of non-agricultural economic specialization, and a more complete dependence of the city on agrarian support areas outside the city than previously supposed.