Provo, Ogden and Salt Lake City in Utah lead among metro areas for having the highest concentration of homes with eight or more rooms, not entirely unexpected give the emphasis the Mormon faith places on raising large families.

But for reasons that are harder to explain, Colorado Springs, at fifth, and Denver, at ninth, also make the top 10 for metro areas with the largest share of large homes, according to an analysis of counts from the U.S. Census Bureau’s 2015 American Community Survey by Lawnstarter.

“There are different reasons in different markets,” said John Egan, editor-in-chief for Lawnstarter, which arranges landscaping service online.

Lawnstarter is based in Austin, Texas, a state known for doing things big. But no Texas city made the top rankings. That’s because basements are rare, which cuts down on how many rooms a home can contain.

The American Community Survey asks participants to count the number of living rooms, dining rooms, kitchens, bedrooms, finished recreation rooms, family rooms and enclosed porches in their homes.

Bathrooms, hallways, unfinished basements, balconies, etc., are excluded. If a dining room flows into a kitchen, that counts as one room. Various room counts are assigned a percentage, including a category for eight or more rooms.

And that’s where Colorado Springs and Denver stand out. In Colorado Springs, 46.3 percent of owner-occupied homes had eight or more rooms, by Census Bureau counts. In Denver, that number was 43.2 percent. Nationally, only 30.2 percent of homes had eight or more rooms.

The gap is a big one. Some of the variation could reflect when the bulk of homes were built, who was buying and the land available to build on.

“When we boomed in the ’90s and early 2000s, that is when everybody wanted the biggest house possible,” said Francie Martinez, a managing broker with Coldwell Banker in Highlands Ranch.

Martinez recalls the home she and her husband built back then. They thought anything under 5,000 square feet wouldn’t be worth the effort, a reflection of the bigger is better mind-set at play.

Colorado also had an influx of Baby Boomers in the 1970s who snapped up larger suburban homes for their families. Now the trend seems headed the other way. Builders still produce large homes, but many try to squeeze more units on the limited land they have.

Young adults flocking to the Front Range are favoring smaller apartments in urban areas, and those who can afford it pay a premium to live in smaller homes in older neighborhoods. The tiny house movement even takes pride in getting by with as little space as possible.

Job growth and migration have greatly outstripped home construction in recent years, leaving a shortage. Getting big homes owned by aging empty-nesters into the hands of young families who need the extra rooms could be one way to provide some relief.

Among the areas with the highest room counts are Centennial and southwest Aurora, Colorado Springs, Monument, Westminster, Northglenn, Greenwood Village and southwest Denver.

Eagle, Summit, Jackson and Grand counties have even higher room counts than metro Denver and Colorado Springs. But big vacation homes skew the numbers in those rural areas, which weren’t included in the study.