Mobility, defined as an individual’s ability to move about effectively in his or her surroundings, is fundamental to independence and quality of life. Mobility disability is highly prevalent in older adult populations, with negative consequences for independence and social connection. Recent models of disability draw attention to the role of environmental factors that can interact with an individual’s underlying impairments to affect mobility independence. This project uses the data from the recently launched National Health and Aging Trends Study (NHATS) to further understanding of the dynamic nature of the disablement process. NHATS, a nationally representative study designed to support the investigation of disability trends and dynamics in later life, uses innovative measures of disability and function, captures both objectively through physical performance measures and subjectively through survey questions. In addition, interviewer observations of each respondent’s residential location provide objective data on the barriers and facilitators in the surrounding built environment.