Where the Number of Large Families Has Increased in the U.S. 'May Come as a Surprise

U.S. census data puts the average household at only 2.58 people, but in some areas of the country there seems to be an upward trend toward having larger families.

The geneology research site MooseRoots compiled data from the last 30 years, identifying areas in the U.S. where large families — those with seven or more members — seem to be increasing or decreasing in number.

Slide the bar at the bottom of this interactive map to see where there has been the greatest amount of change in the prevalence of large families:

Here's a look at where the presence of large families has had its largest increase and decrease between 1980 and 2010:

"As expected, Utah has remained a leader in large families over the past couple of decades," Find The Best's historical census data stated of MooseRoots' findings. "But the West Coast and heart of the country has seen a rise in families with seven or more members, which may come as a surprise. The Northeastern families are having fewer children."

To put all of this into perspective though, MooseRoots pointed out that in 1790, about half of the families in the United States had at least six members. By 2010, only about 5 percent of families in the U.S. were considered large. About 66 percent of the population in 2010 was represented as a small family composed of one to three members.

The population as a whole in 2010, was 77 times larger than in 1790.

The website BabyCenter reported sociologists saying that bigger families are not an increasing trend around the country, but acknowledging some areas of the country might experience large family baby booms, as indicated in MooseRoot's data.

"You do get clusters of behavior that are very real," Duke University sociologist and demographer Philip Morgan told BabyCenter. "But it's not appropriate to generalize them across the country, because there are other pockets that are behaving very differently."

"My forecast is more of the same in the United States," he added. "There are people who want substantially more than the two-kid average, but that's been going on for a long time."