Where Americans Are Having the Most Children

The measure behind this story is simpler than most people expect. The Census Bureau's American Community Survey asks women aged 15 to 50 whether they gave birth in the past 12 months, then reports the answer as births per 1,000 women in that age range. It's a snapshot of recent fertility, not a lifetime count, which makes it useful for spotting where childbearing is concentrated right now. The national figure is 51.3 births per 1,000 women. Hold that number in mind, because the places at the top of the list sit well above it.

Start with states. The leaders cluster in the Plains and the Mountain West, far from the coasts where most population growth gets discussed. South Dakota ranks first at 65.0, followed by North Dakota at 62.5 and Wyoming at 62.3. Kansas comes next at 59.9, then Mississippi at 58.7, Nebraska at 58.4, and Hawaii at 58.2. Six of those seven are interior states with small populations and large rural shares. Mississippi is the exception to the geography but fits a different pattern, with younger marriage and earlier childbearing than the national average.

Look across this list and the pattern is consistent enough to call it a formula. Lower-density states with younger median ages, more married households, and stronger religious participation post higher recent fertility. The gap between South Dakota and the national rate is almost 14 births per 1,000 women, which is large when you remember this is a single-year measure. You can see the full ordering on the highest-fertility-rate states ranking.

The county map tells a sharper story

State averages flatten out local extremes. Counties don't. When you filter to counties with more than 200,000 people, so the rates rest on solid sample sizes, the leaders separate into a few clear types. The same drivers show up again and again, and each one is identifiable.

The single highest county on this list is Onslow County in North Carolina at 92.6, more than 40 points above the national rate. Onslow is home to Camp Lejeune, one of the largest Marine Corps installations in the country. Military base counties skew young and married, with steady incomes and family housing, and that combination pushes recent fertility up hard. Okaloosa County in Florida, at 70.4, runs on the same logic with Eglin Air Force Base anchoring its workforce.

The second driver is religious community. Ocean County, New Jersey sits at 82.7, lifted by the large Orthodox Jewish population in Lakewood, where family sizes run well above the secular norm. Rockland County, New York follows at 79.9 and Orange County, New York at 70.7, both shaped by large Hasidic communities. Utah County, Utah lands at 73.9. It's heavily Latter-day Saint and home to Brigham Young University, a combination of religious tradition and a young married student population that keeps childbearing high.

The third driver is agricultural Hispanic population. Yakima County, Washington, at 69.2, is a farming region with a large Hispanic share, and Hispanic fertility has historically run above the national average. The remaining high counties round out the picture: Guadalupe County, Texas at 72.1, Jefferson Parish, Louisiana at 69.8, and Clayton County, Georgia at 69.6.

Why the drivers matter more than the geography

It would be easy to read the state list and conclude that fertility is simply a rural Plains phenomenon. The county data corrects that. Onslow and Okaloosa are coastal. Ocean and Rockland sit inside dense metropolitan regions near New York City. What these places share isn't a region, it's a population structure. A base full of young enlisted families, a community where large families are the cultural expectation, or a farming economy with a young workforce will all produce high recent fertility regardless of latitude.

That's also why the highest-fertility counties beat the highest-fertility states by such wide margins. A state rate averages millions of women across every kind of household. A county like Onslow concentrates one demographic type, and the measure responds. The 92.6 at the top is not a different country, it's the same survey question answered by a population built for it.

One caution on reading these numbers. Births per 1,000 women aged 15 to 50 in a single year moves with age structure. A county with an unusually young adult population can post a high rate without families being especially large, simply because more women are in their peak childbearing years. The military base counties carry some of that effect. The religious-community counties carry the opposite, with larger completed family sizes doing more of the work. Both land high on the same scale for different underlying reasons.

If you want to see how your own county compares, the full highest-fertility-rate counties ranking lays out the order, and the compare tool lets you put any two places side by side on the same measure. The interesting work starts when you stop reading the leaders and start asking which of these three drivers, base, faith, or farm, is shaping the place you actually live.

Sources

Data is from the U.S. Census Bureau American Community Survey, which reports births per 1,000 women aged 15 to 50 in the past year. Rankings referenced: highest-fertility-rate states and highest-fertility-rate counties.