The Washington region, especially the western part, remains among the strongest in the United States for job growth, with Loudoun County tying Clark County, Nev., for the nation's biggest percentage increase in employment and Prince William County right behind, according to new government data.

"There's just been phenomenal job growth in the D.C. area, especially on the Virginia side," said Gina Martin, an economics research analyst with Wachovia Securities Inc.

Loudoun and Clark (home of Las Vegas) counties each had a job-growth rate of 5.2 percent from December 2002 to December 2003, the Bureau of Labor Statistics reported yesterday. That compared with zero job growth for the nation.

Prince William County had the next-largest increase, with 5.1 percent, and Frederick County was 10th in the nation, with 3.8 percent.

Fairfax County ranked fifth in the nation in total number of jobs gained -- 18,500 -- over the same period.

"Loudoun, Prince William, Fairfax and Frederick -- that geography tells you the whole story: There's a shift to the western part of the Washington region, which is becoming a major employment center," said Larry Rosenstrauch, director of the Loudoun County Department of Economic Development. "All those counties touch each other."

The District, meanwhile, had 0.4 percent fewer jobs in December 2003 than in December 2002.

The government did not release data yesterday on which sectors created the jobs. But economists said government hiring played a role in the Washington area. And more people are moving into the outer counties of the region, creating a demand for goods and services.

The Washington area "has just been sheltered from the economic downturn to some extent, largely due to government influence, but also due to defense contracts and the large biomedical presence in the region and a diverse sort of economy," Martin said.

Some local jurisdictions also ranked in the top 10 nationally for highest weekly wages in the fourth quarter of 2003, including the District ($1,238), Arlington County ($1,199) and Fairfax County ($1,158). In contrast, Loudoun County's average weekly wage was $965, while Prince William County's was $688.

New York City's average weekly wage was $1,480, the highest in the nation. The national average was $767.

Population growth was a big factor in Loudoun County's surge, economists said. In April, the U.S. Census Bureau reported that the county's population increased 30.7 percent -- from an estimated 169,599 in April 2000 to 221,746 in July 2003. The additional 52,147 residents made Loudoun the fastest-growing county, by percentage, in the nation.

"And all those people require services," Rosenstrauch said. "New citizens [of Loudoun County] with high wages require doctors and lawyers. They also require landscapers and construction contractors."

Loudoun County is hiring about 500 new teachers a year, he said. It also has seen growth in the retail industry, with the additions of Costco, Target, Giant and Wegmans.

Tricia Hankinson, an analyst with the county's economic development department, said earlier data showed a 17 percent increase in federal government jobs in the county from second quarter 2002 to second quarter 2003. She said jobs in the financial, insurance and real estate sectors increased 16 percent.

Rosenstrauch said some of the new government jobs involve Homeland Security at Washington Dulles International Airport, in the eastern edge of the county.