This User Guide focuses on the information relevant to disability contained in the American Community Survey (ACS), a nationally representative survey of households and “group quarters” (GQ) populations conducted by the U.S. Census Bureau. The ACS is a valuable source of disability information, making it possible for researchers and policymakers to track changes in prevalence rates, employment and economic indicators across states and over time. It provides vital information on how the labor market and the social and policy environments may influence the status and economic well-being of the population with disabilities. The ACS offers researchers and others a tremendous amount of population-based information that can be used in a myriad of ways, from identifying potential populations and localities in need of services to providing baseline measures for comparison to other studies. The ACS is invaluable for the purposes of monitoring the progress of the population with disabilities and is an important component of the nation’s efforts to reach the goals of full participation, independent living, and economic self-sufficiency for the population with disabilities. Cornell University produced the original series of User Guides to disability data sources as a part of its Rehabilitation Research and Training Center on Disability Demographics and Statistics designed to bridge the divide between the sources of disability data and the users of disability statistics. This ACS User Guide is an update and extension of the original guide written by Robert Weathers in 2005. It has been produced in collaboration with the University of Texas Medical Branch under funding from the National Institutes of Health, and contains valuable information on the disability population that can be used to inform rehabilitation researchers and other disability data users.