In this paper, we investigate residents’ definitions of their own neighborhoods and the salience of neighborhoods for daily life in Los Angeles County. We use data from a new survey, fielded in 2000-2001, that was specifically designed to test hypotheses about neighborhood effects on children and adults. Known as the Los Angeles Family and Neighborhood Survey (or L.A.FANS), this survey collects data on approximately 40 households in each of 65 neighborhoods in Los Angeles County. As described below, respondents were asked to report on the size of their neighborhood and the geographic location of regular activities for themselves and their children (e.g., work, school, and shopping). Detailed data are also collected on family social and economic status and background as well as a variety of child and family behaviors and outcomes. In our analysis, we concentrate on locations that adult respondents spend their time, including work places, grocery stores, religious institutions, and health care providers.