The American Community Survey (ACS) is a Census Bureau program that provides annually updated information on demographic, social, economic, and housing characteristics of U.S. households at every level of geography, from the nation to the neighborhood. ACS data are used by public and business decision-makers to more clearly identify issues and opportunities and more effectively allocate scarce resources to address them. While the ACS is a relatively new program (full implementation began in 2005), it is the most recent iteration of a long-standing federal tradition of using the decennial census to collect socioeconomic data (that is, data other than traditional demographic data of age, sex, race, and ethnicity) to inform public policy. An analysis of federal domestic assistance program expenditures distributed on the basis of American Community Survey-related data indicates that: (1) The accuracy of the American Community Survey (ACS) will determine the geographic distribution of a substantial proportion of federal assistance, particularly in the form of grants; (2) The bulk of ACS-guided federal assistance goes to state governments through a handful of large formula grant programs to aid low-income households and support highway infrastructure; (3) State per capita ACS-guided funding is positively related to income inequality (high annual pay, high poverty), Medicaid income limits, and the percent of the population that is rural; and (4) The ACS facilitates the distribution of federal assistance largely by serving as the basis for six other federal datasets. Most important of these are the Bureau of Economic Analysis' per capita income series and the Census Bureau's population estimates. This report's analysis of the distribution of federal funds on the basis of ACS-related data has significant implications for federal, state, and local stakeholders. The nation receives a very substantial return on its investment in ACS-related datasets. Through improved understanding of individual federal program reliance on ACS-related data, the Census Bureau will be better able to provide data and indicators that fit program needs. Advocates for communities and lower-income households now have a dollar-specific rationale for encouraging households to participate in the ACS. State governments have much to gain financially from a more accurate and reliable ACS. (Contains 1 figure, 8 tables and 46 endnotes.)