Douglas County had 137 fewer people in 2006 than it did in 2005, according to the U.S. Census.
Steady increases over the past three decades have fueled debate on the county's growth rate.
According to the census, Douglas County had 354 births and 416 deaths in 2006.
The census claims that 134 people moved out of the county during the year.
Federal figures are based on administrative records, such as births and deaths and migration information gleaned from tax returns, Medicare and Medicaid records, according to Nevada Demographer Jeff Hardcastle.
"Their numbers are counter to what we've been seeing in our state-generated analysis," he said. "Our estimates are based on housing and regression estimates that showed Douglas actually growing by 3 percent."
The Nevada Legislature bases its decisions on the state demographer's numbers while the census estimates are used for some federal programs.
Valley residents on both sides of the growth debate questioned the numbers, but agreed Douglas growth has slowed.
Former Assembly Minority Leader and Coalition for Smart Growth spokesman Lynn Hettrick said he doubted state and federal numbers will agree.
"I think the census figures disagreed with the state demographer when the census was taken back in 2000," he said. "A little bit of this debate is whose numbers do we believe."
Jim Slade, an outspoken critic of the state demographer's Office, said he hasn't seen the figures yet.
"I've always been somewhat mystified by the methodology used by both the Census and the state demographer," he said.
Both men agreed that market forces have shown a slow-down in the county's population growth.
"I would certainly believe that our growth has slowed because of market conditions," Slade said. "That's reflected in the fewer building permits issued by the county. But it's hard for me to believe we've actually lost population."
Hettrick said housing in Douglas County is relatively expensive.
"When the economy softens, that makes it harder to build a house here," he said. "People worry about income and banks worry a bit more about the ability to pay."
Before the 1970s, Nevada's population experienced huge swings as new residents followed booms caused by mining and construction projects.
"This is part of what we've said all along," Hettrick said. "When things are great, we see a lot of growth. But it always happens that cycles occur and when they occur, we see it slow down."
Year Census State
2000 41,259 41,674
2001 42,226 43,450
2002 43,225 44,212
2003 44,134 45,603
2004 45,876 47,803
2005 46,046 50,108
2006 45,909 51,770
