The Institute for Health Metrics and Evaluation has finished a county-level study of life expectancy in the United States from 1987 to 2007. They compared their information to an average of the 10 nations with the world’s best life expectancies, called the "international frontier."
Each county is shaded according to its relationship to the frontier. If a county is shaded light red, it is not far at all behind the frontier. If it’s dark red, well, let’s take the darkest red on the male life expectancy map; Beltrami County is 18 years behind the frontier. That means that the most advanced nations reached Beltrami’s current levels in 1993.
For a full discussion of the data, read the related post: Life expectancy in your county.