Dr. Ali Mokdad of the Institute for Health Metrics and Evaluation in Seattle and colleagues analyzed new mortality data by age, sex and county from 1989 to 2009.
Across U.S. counties, life expectancy in 2009 ranged from 66.1 to 81.6 years for men and 73.5 to 86.0 years for women. From 1989 to 2009, life expectancy for men improved by 4.6 years on average but the increase for women 2.7 years.
Throughout the country, women were more likely than men to have no progress in life expectancy or to have their lifespan get shorter over time, Mokdad said.
"It's tragic that in a country as wealthy as the United States and with all the medical expertise we have that so many girls will live shorter lives than their mothers," Mokdad said in a statement.
Women were living longest in Collier, Fla., 85.8 years on average, and shortest in McDowell, W.Va., 74.1 -- an 11.7-year gap. In 1989, the gap was 8.7 years.
The overall gap was larger for men -- 15.5 years -- but it has grown by less than a year since 1989.
Men live the longest in Marin, Calif., to age 81.6. Men lived the shortest, on average, in Quitman and Tunica, Miss., to age 66.1.