A new study by the Journal of American Medical Association (JAMA) reveals the average lifespan was just over 79 years in 2014, a five-year increase from 1980.
But there was a huge geographical gap where several counties in North and South Dakota had life expectancies 20 years lower than some counties in central Colorado like Summit County.
Lifespan also increased along both coasts, while many Southern counties had very little improvement.
Experts say this gap is most likely due to differences in economic factors, obesity, smoking, education, race and health care access.
For more information: US Department of Health and Human Services.