This study measures how Kenyan farmers and farming systems have responded to changes in population density and associated land pressures. Kenya is a relatively densely populated area, with 40% of its rural people residing on 5% of its rural land. We develop a structural model for estimating the impact of population density on input and output prices, farm size, and ultimately on smallholder behavior and agricultural intensification. Evidence is derived from a five-round panel survey between 1997 and 2010. We find a negative relationship between localized population density and farm size, and a positive relationship between population density and measures of land intensification up to roughly 500persons/km2. Beyond this threshold, rising population density is not associated with further increases in land intensification. Some measures of intensification actually show an alarming decline beyond this population density threshold. We also find a relatively weak relationship between population density and off-farm income. Overall, total household income per adult equivalent is found to decline significantly as population density rises. These findings raise serious policy questions about feasible pathways for rural poverty reduction in the context of increasingly land-constrained farming systems. © 2014.