Sound management of large carnivore populations in wildland–urban environments requires accurate information regarding the ecology of these populations and factors contributing to their interactions with people. We quantified cougar (Puma concolor) residential use and interactions with people in western Washington from 2003 to 2008 to characterize the ecology and risks associated with an adaptable large carnivore residing in a wildland–urban environment. We fitted cougars with global positioning system and very-high-frequency radiocollars, quantified residential use, and tested for differences between demographic classes using analysis of variance fixed-effects and multiple-comparison models. We investigated interaction reports to quantify interaction rates and tested for differences among interaction levels for different cougar demographic classes. We captured 32 cougars (16 males and 16 females) and estimated 33 annual utilization distributions (UDs) for 27 individuals. Ninety-three percent of cougars (n = 27; 15 males and 12 females) used residential areas with an average UD overlap of 16.86% (SD = 17.05%, n = 33). There were no differences between male and female (F_1,29 = 0.77, P = 0.49) or resident and transient (F_1,29 = 0.0003, P = 0.99) use of residential areas, but subadult use was significantly higher than that of adults (F_1,29 = 7.20, P = 0.01). Twenty-nine percent of reports were confirmed (n = 73), with livestock depredations accounting for 67% of confirmed reports. The interaction rate for radiocollared cougars was low (1.6 interactions/1,000 radiodays) and all demographic classes were involved in similar numbers of interactions. Use of residential areas in western Washington appears to be a function of the adaptive and mobile nature of the cougar exploiting suitable habitat and resources within the matrix of residential development. Interaction appears to be a function of individual behavior. Management strategies that target problem individuals and maintain older age structures in local populations coupled with proactive landscape planning and public education in residential areas at the wildland–urban interface may provide an effective strategy for decreasing cougar–human interaction.