Classic Period lowland Maya urban centers often lack sharp boundaries due to progressive dispersal of residential settlement. This dispersal gives rise to questions about the concept of site and the notion of community affiliation. Research on settlement patterns at Chunchucmil, an urban center in NW Yucatan, Mexico, dating to the 5th and 6th centuries A.D., explores the issue of site boundaries and the social and economic implications of such boundaries. Detailed mapping, test pitting, and reconnaissance reveal that Chunchucmil had three densely occupied, concentric, contemporaneous zones of settlement covering between 20 and 25 sq km and inhabited by a population of up to 42,500. Data from both within and beyond the density thresholds marking the edge of the city imply the existence of communities whose boundaries do not always follow those of the site. A portion of the hinterland settlement close to the edge of the city shows stronger economic and social connections with the city, for example. These connections enable the delineation of Greater Chunchucmil, extending 5 km from Chunchucmil’s center. The work at Chunchucmil also allows comparison with other large Maya cities that have been systematically documented. This comparison highlights considerable variability in Maya urban forms and in how these cities relate to their peripheries.