Counties With the Best Life Expectancy: Where Americans Live Longest

The average American lives to about 77.5 years, but that number hides a stunning range. Residents of the highest-ranked U.S. counties outlive residents of the lowest-ranked ones by nearly two decades, a gap wider than the difference between the U.S. average and some of the world's poorest nations.

The Counties at the Top

Summit County, Colorado consistently ranks among the top counties in the United States for life expectancy, with residents averaging roughly 86 to 87 years. Marin County, California sits close behind, as do several counties in Utah, including Morgan and Summit counties, where Church of Jesus Christ of Latter-day Saints membership drives low rates of smoking and alcohol use. Douglas County, Colorado and Fairfax County, Virginia also appear near the top of most county-level analyses, with average life expectancies exceeding 84 years.

For context, Monaco leads the world in 2026 at 86.73 years. Japan sits at 85.15 years. The top U.S. counties are genuinely competitive with the longest-lived nations on earth.

What Actually Drives These Numbers

Three factors explain most of the gap between high and low-longevity counties.

Income and wealth. Summit County, Colorado has a median household income well above the national median. Fairfax County, Virginia is one of the wealthiest counties in the country. Higher income means better access to healthcare, lower rates of chronic stress, and more options for diet and exercise. The correlation between county-level median income and life expectancy is close to linear.

Behavioral and cultural factors. Utah counties punch above their income weight on longevity because a large share of residents avoid tobacco and alcohol entirely. This is not a small effect. Smoking alone accounts for roughly 30 percent of the gap between the highest and lowest life expectancy counties in the U.S.

Geography and environment. High-altitude Colorado counties have lower rates of obesity and cardiovascular disease. Coastal California counties with warm climates and outdoor culture see higher rates of physical activity. These environmental signals compound over decades.

The Bottom of the Map

The lowest life expectancy counties in the U.S. are concentrated in three regions: the Mississippi Delta, Appalachian Kentucky and West Virginia, and the Lakota Sioux reservation counties of South Dakota. Oglala Lakota County, South Dakota recorded an average life expectancy below 67 years in the most recent county-level data available (as of late 2025). That is lower than Bangladesh.

South Carolina ranks among the 10 lowest states in the nation for life expectancy, driven by high rates of cardiovascular disease, diabetes, and limited rural healthcare access. Several counties in the state fall well below the national average.

The gap is not random. It tracks directly with poverty rates, insurance coverage, rates of chronic disease, and access to primary care physicians. Counties with fewer than one primary care physician per 3,500 residents have measurably shorter average lifespans.

What This Means If You're Choosing Where to Live

Longevity is not just a health statistic. It is a financial planning variable. If you retire at 65 in a high-longevity county, you need to plan for 20 or more years of retirement income. If your county's average life expectancy is 74, your financial assumptions look completely different.

This is where taxes and cost of living intersect directly with longevity data. Colorado, Utah, and Virginia, three of the states home to the top-performing counties, all have relatively competitive income tax structures compared to high-cost states. You can live longer and keep more of your money. That combination is rare and worth mapping carefully.

If you are weighing a retirement move, states with no tax on Social Security income and lower overall cost of living can extend how far your savings reach across a longer-than-average lifespan. See our breakdown of states that don't tax Social Security and our guide to the best states for retirees to avoid taxes for the full picture. For those thinking about what they leave behind, estate tax exposure by state matters more when you live longer.

Use our state comparison calculator to stack your current state against a target state across taxes, cost of living, and other quality-of-life metrics.

Key Takeaways

• The top U.S. counties, including Summit County, Colorado and Marin County, California, have average life expectancies of 86 to 87 years, rivaling the global leaders Monaco (86.73) and Japan (85.15).
• The gap between the highest and lowest life expectancy counties in the U.S. is approximately 20 years, with some Appalachian and Delta counties averaging below 67 years.
• Income, tobacco and alcohol use rates, and access to primary care explain the majority of county-level longevity differences, making where you live a measurable health decision, not just a lifestyle preference.

Compare states side by side at Live or Die Here to see how your current location stacks up on every factor that affects how long, and how well, your money and your health hold out.