To identify the healthiest county in every state, 24/7 Wall St. reviewed county-level data from County Health Rankings & Roadmaps, a Robert Wood Johnson Foundation and University of Wisconsin Population Health Institute joint program. Rankings are based on overall health outcomes — a weighted composite of length of life, quality of life, and maternal health — and overall health factors. The health factors component is itself a weighted composite of health behaviors, clinical care, social and economic factors, and physical environment measures. Data was compiled from more than 20 different sources and is for the most recent year available. A total of 3,142 counties and county equivalents were considered. In the case of ties, counties that ranked higher in behavioral measures were considered healthier. Median household income, the share of adults with a bachelor’s degree, poverty rates, and uninsured rates are five-year estimates from the U.S. Census Bureau’s 2017 American Community Survey.