For Clark County, the population estimated at 1,954,319 in 2007 is projected to grow by 54 percent to just over 3 million by 2028, according to the projections.

But the real boom will be in some of the smaller counties. Nye County, for example, is projected to grow by 84 percent to nearly 85,000 residents by 2028.

In Lyon County, east of the capital city, the growth rate will be 89 percent to more than 105,000. In much smaller Storey County, also next to the capital, the growth rate will be 86 percent to more than 8,000, according to the data.

Although growth is not in dispute over the long term, there is some uncertainty about the immediate future, Hardcastle said.

Of particular concern is the impact of new hotel projects opening on the Strip between now and 2012.

About 32,000 hotel rooms are in some stage of development to be added to the Southern Nevada casino corridor's hotel inventory. But one scenario suggests that not all these rooms will be fully occupied, and gaming revenue increases will not match the total room expansion. That means less population growth from the construction than might otherwise be expected, he said.

"It used to be that if you build it, they will come," Hardcastle said. "Now it's if you build it, they may not come as much."

The report suggests that population changes will be uneven around the state.

Northwestern Nevada, including Carson City and Churchill, Douglas, Lyon, Storey and Washoe counties, is projected to grow by more than 226,000 people.

Rural Nevada, made up of Elko, Esmeralda, Eureka, Humboldt, Lander, Lincoln, Mineral, Pershing and White Pine counties, is experiencing mining growth and that may last through the next 20 years.

Southern Nevada, composed of Clark and Nye counties, is projected to grow by more than 1.1 million people.

The projections are used in preparing the state's budget and for other planning purposes.

They were prepared using a model that relates a county's population and economy to other counties in the model and the nation as a whole.

The State Demographer's Office is part of the Nevada Small Business Development Center at the College of Business Administration at the University of Nevada, Reno. It is funded by the Nevada Department of Taxation.

Contact Capital Bureau reporter Sean Whaley at swhaley@reviewjournal.com or 775-687-3900.