Participation in preschool programs has been associated with a number of positive outcomes. Evaluating data from the 40-year follow-up to the High/Scope Perry Preschool Program Study, Belfield and his colleagues show how preschool participation by low income children relates to significant economic benefits both to the children by the time they are in their 40s and to society more generally (Belfield et al. 2006). Summarizing over 160 studies conducted from 1960 through 2000, Camilli et al. found that preschool had a range of shorter and longer term positive relationships to cognitive gains, progression through school, and social-emotional development (Camilli et al. 2010). This report provides an overview of state supported preschool enrollment and state funding of preschool programs. Information provided here is based primarily on data collected from state agencies that manage preschool programs through the State of Preschool 2012-13 data collection. Officials in states with state preschool programs were the respondents to the data collection effort. Data collection occurred between November 2013 and March 2014. Forty states and the District of Columbia operated 53 programs in 2012-13 (see Carolan et al. forthcoming). Two additional data sources are utilized in the report. Comparisons are made to data collected through the State of Preschool 2011-12 data collection. Population counts for determining the percentage of 3- and 4-year-olds in each state that are enrolled in state supported preschool programs were obtained from U.S. Census Population Estimates, State Population Datasets. The Census Bureau's Population Estimates Program (PEP) uses data on births, deaths, and migration to calculate population change since the most recent decennial census. Details about the data sources used in the report are provided in the appendices. Three appendices provide: (1) Technical Notes; (2) Glossary; and (3) Support Tables. [This report was prepared in part under Contract No. ED-IES-13-C-0055 with the National Institute for Early Education Research, Rutgers University.]