The prehistoric establishment and expansion of permanent settlements on the Northern Channel Islands of southern California generally follows a pattern predicted by the population ecology model, the ideal free distribution (IFD). We determine this by comparing the abundant archaeological record of these Islands against a careful quantification of habitat suitability using areal photography, satellite imagery, and field studies. We assess watershed area, length of rocky intertidal zone, length of sandy beach for plank canoe pull-outs and area of off-shore kelp beds, for 46 coastal locations. A simple descriptive anal- ysis supports key IFD predictions. A Bayesian model fitted with the Gibbs sampler allows us to recon- struct the Native assessment of habitat that appears to underlie this process. Use of the Gibbs sampler mitigates the impact of missing data, censored variables, and uncertainty in radiocarbon dates; it allows us to predict where new settlements may yet be discovered. Theoretically, our results support a behav- ioral ecology interpretation of settlement history, human population expansion, and economic intensifi- cation in this region. They also demonstrate Bayesian analytical methods capable of making full use of the information available in archaeological datasets.