Life expectancy fell by 1.5 years in the United States in 2020. The decline, driven by the COVID-19 pandemic and the opioid crisis, represents the most pronounced regression in public health in the United States since World War II.

While the most recent dip in life expectancy in the U.S. is alarming, there are many parts of the country where poor health outcomes and other socioeconomic hardships have long been the norm.

Using an index of three measures -- life expectancy at birth, bachelor's degree attainment, and poverty rate -- 24/7 Wall St. identified the worst counties to live in in every state.

Big Horn County, Wyoming, is located in the north-central part of the state along the Montana state border. The most consequential industries in the area include gas and oil extraction, mining, farming, and ranching -- but jobs in these sectors do not appear to be providing for local residents in the same way jobs in much of the rest of the state are. The typical area household earns only $52,804 a year, well below the median household income across the state of $64,049. Additionally, local residents are slightly more likely to live below the poverty line than the typical Wyoming resident.

Life expectancy in the county also lags considerably behind much of the rest of the state. At birth, life expectancy in Big Horn County is 76.1 years, compared to the 78.9 year average across Wyoming.

Data on bachelor's degree attainment and poverty are from the 2019 U.S. Census Bureau's American Community Survey and are five-year estimates. Data on average life expectancy at birth came from the 2021 County Health Rankings, a joint program of the Robert Wood Johnson Foundation and University of Wisconsin Population Health Institute, and are based on mortality data from the years 2017 to 2019. Supplemental data on population and income are from the ACS, and unemployment rates are seasonally adjusted for May 2021 and are from the Bureau of Labor Statistics. This is the worst county to live in every state.