Utah's spurt came with the nation's overall growth rate dipping to its "lowest point since before the baby boom" at the end of World War II, Census Bureau Director Robert Groves said in a news release.
The U.S. population increased by 0.9 percent to 311.6 million people.
Most of Utah's gains resulted from "natural increase," more births than deaths. That added 47,422 people or 89 percent of the growth while immigration accounted for 11 percent.
"We ranked No. 1 in births in the nation, and No. 51 in deaths," said Pam Perlich, senior research economist at the University of Utah. "It's because of our age structure. We have fewer older people, so we have fewer deaths, and we have a lot of young people."
David Stringfellow, senior economist at the Governor's Office of Planning and Budget, also pointed to the state's demographic differences.
"Utah's internal population dynamics are different from the nation's. We have a lot more births and a lot fewer deaths," he said. "So we always have strong internal growth in population even during times of economic recession when people hunker down and don't move around the country very much."
The Census Bureau estimated that a net of 5,912 people immigrated to Utah between April 2010 and July 2011.
"In the days before the recession," Perlich said, "we had a net in-migration of 30,000 people a year. So this is just a fraction of that number."
"It's because of the recession," she added, with jobs no longer acting as a magnet for immigration as they did during the booming early 2000s. "That, plus a lot of people nationally owe more on their mortgages than their houses are worth, so they are stuck even if they had prospects of a job elsewhere."
Still, Stringfellow said, Utah's numbers "appear to be on the way back up relative to some other places."
The Census Bureau pegged almost all immigration to Utah as international, not domestic. It estimated that a net of 6,738 people from other countries moved into the state during the latest time frame. It calculated that Utah had a net loss in domestic immigration of 826 people to other states.
Stringfellow said some of the "international migration may be from LDS missionaries returning home from abroad or from a draw to local universities and colleges" as well as people with work permits.
He said Census estimates do not say how much of that international migration may be from undocumented immigrants. But Perlich said, at the peak of the economic boom, estimates were that about half the international immigration to Utah came from undocumented immigrants.
Perlich noted that the international immigration numbers for Utah are low enough "that it probably shows that a lot of people are going home" as well as coming from abroad.
She said several factors are keeping Utah's population growth below the peaks it hit before the recession.
First, women born in the 1980s as part of a "baby boom echo" are now aging beyond their prime childbearing years, so births have been dropping. Many families also have fewer children during tough economic times.
Perlich also pointed out that two generations ago, Utah women with the influence of the family-friendly Mormon culture averaged having five children. "Now it's down to 2.5," she said, "compared to a national average of 2.1."
A tough economy may persist for "at least another five years," she said, reining in immigration and births.
"It happens to be the biggest boom and bust since the Great Depression," Perlich said. "So everything is grinding to a screeching halt for now. But there are huge swaths of our nation that are in economic devastation that is extensive and extreme. Here we have not had that. The boom was not as high, the bust was not as low. So while things have slowed, we are not in a catastrophic economic situation."