This is the last in a series of articles on Tuesday’s General Assembly primaries in Northern Virginia. For more, visit

On either side of Gallberry Terrace, building crews are everywhere — hammering nails into the frame of houses and sawing pieces of plywood in yards still bare of grass.

The sounds of construction can be heard throughout Loudoun County’s Stone Ridge, a Truman Show-esque planned community with its own parks, schools and shops.

The half-built row of seven townhouses are dressed in massive green tarps. Virtually every one of them boasts a red Too late, Sold! sign.

A decade ago, the last time the census released numbers before this year, this land was comprised of empty fields. Today, it’s home to more than 5,000 people.

“We thought with all the stuff happening with the economy, they’d stop building,’’ said Justin Whitmer, who bought a Gallberry Terrace home with his wife four months ago. “That didn’t happen.”

Stone Ridge — and the other developments that have popped up seemingly overnight — contributed to the half-million new residents that crowded into Northern Virginia in the last decade, forcing lawmakers to shift the state’s political boundaries.

The growth has led the region to gain one seat in the Senate and three in the House of Delegates — all in the thriving outer suburbs of Loudoun and Prince William counties. Rural parts of the state, once home to farms and factories, have seen their political representation decline as lost jobs led to an exodus.

This new Virginia was born when people moved farther away from the District as jobs became more plentiful, families looked for more space and homeowners searched for the more affordable.

“The creation of the new 13th district is something that was long recognized as coming because of the growth we’re seeing,’’ said Prince William Supervisor John T. Stirrup, who is running for state Senate. “We could see the shift.”

Republican candidates

A trio of Republicans in the 13th Senate District have spent months knocking on doors in advance of Tuesday’s primary, trying to win the opportunity to take on a Democrat in November’s general election.

The three agree on most major issues — opposing tax hikes, cracking down on illegal immigration and scaling back the skyrocketing cost of extending Metro to Dulles airport — but differ in their styles and backgrounds.

No matter who wins, lawmakers in Northern Virginia, long frustrated that so many of the region’s tax dollars are sent to other parts of the state, will gain clout in Richmond as the state continues a steady power shift north to the Washington suburbs.

Northern Virginia — which will soon boast 12 senators and 29 delegates — will host nine primaries Tuesday, more than any other area of the state. Democrats looking to hold onto their slim majority in the Senate see the new seat, moved from a Republican district in Hampton Roads, as a place to possibly pick up ground in the chamber.

In the 13th district, Stirrup faces former Loudoun delegate Dick Black, known as one of the most conservative voices in the House, and Prince William chief deputy clerk Bob FitzSimmonds, a previously unsuccessful candidate for Senate.

Much of the new district, which takes in parts of eastern Loudoun and Prince William, has been represented by Democratic Sen. Mark Herring since 2006. But his Loudoun district had 130,000 more people than 10 years ago when the district lines were last drawn.

Senate districts are supposed to have a population of 200,000. In 2001, 186,000 people called Herring’s district home. By 2011, that number had ballooned to 316,000.

Senate leaders carved the district this summer as part of the once-a-decade redistricting process in which they redrew lines for all 140 General Assembly seats — creating a GOP-leaning district carried by former senator George Allen in 2006, Sen. John McCain (Ariz.) in the 2008 presidential election and Gov. Robert F. McDonnell in 2009, all Republicans.

Northern Virginia — particularly the inner suburbs of Arlington, Alexandria and eastern Fairfax — has reliably voted for Democrats, but the outer suburbs teetered back and forth between both parties in recent years, helping create Virginia’s reputation a swing state.

“I don’t think you can take anything for granted,’’ Black said. “There can be fairly rapid shifts. The Republicans have an advantage, but we still have a tough battle on our hands.”

Black, a lawyer who served in the House for eight years until he was defeated in 2005, is perhaps best known for distributing plastic models of fetuses to lawmakers preparing to vote on abortion bills.

He worries about Democrats’ actions in Richmond and Washington, which he said have led to lost jobs and home foreclosures. “I think the nation really faces perilous times,’’ he said. “Some of the policies we’re seeing are dangerous, failed social experiments.”

Democrat Shawn Mitchell, an Iraq veteran and small-business owner from Loudoun, jumped in the race after he said he determined the other candidates were not business minded enough. “There is a tremendous amount of independence in the district,’’ Mitchell said.

Diversity and affluence

Residents mostly talk about their desire to pump more money into schools to alleviate crowding and into relieving traffic congestion in a district that continues to grow, where the average commute was 38 minutes, based on a review by George Mason University’s Center for Regional Analysis.

The district is one of the state’s most diverse, too. While some parts boast rolling hills, lush green fields and massive trees, other sections have given way to development after development as Washington’s sprawl stretches further west.

Hispanics and Asian-Americans have arrived in droves, as have people who work for nearby defense contractors, technology companies and Dulles International Airport. Asian Americans make up nearly 15 percent of the Senate district, while Hispanics make up close to 10 percent. About 11 percent of district residents were foreign-born, according to GMU.

Stirrup, a supervisor who has represented the Gainsville district for eight years, has supported tougher immigration laws and measured growth. He helped get a new immigration policy passed and was one of two supervisors to vote against the county’s 2012 budget because it will raise taxes slightly.

The former transportation association lobbyist and political appointee during the Reagan administration, and Black both had raised about $145,000, as of last week. FitzSimmonds has raised $51,000.

In Prince William, which grew by 98,000 in the last decade, there are places like Dominion Valley with 3,000 houses, and the Piedmont golf community with 1,600 homes, as well as new shopping centers, megachurches and schools.

In Loudoun, which grew by 142,000 and has been dubbed one of fastest growing and most affluent counties in the nation, there are massive planned communities like South Riding and Broadlands, where thousands of homes have meant new firehouses, stores, schools and roads.

Black said he has an edge because he is the only one of the three Republicans who lives in Loudoun, which comprises three-quarters of the district. But FitzSimmonds, who worked for Del. Scott Lingamfelter (R-Prince William) and former senator Ken Cuccinelli II, now attorney general, said he has name recognition because of his two previous runs for a nearby Senate seat in 1999 and 2007 against Democrat Charles J. Colgan.

FitzSimmonds, who owns a small business, stresses the need to reduce the size of government and spending both at the state and federal levels. “I am tremendously concerned about the burden of government,’’ he said. “I’m tired of paying the federal government for getting in my way.”

At Stone Ridge, stone facades and cream-colored homes are on roads called Destiny Drive and Opportunity Way. There are swimming pools, community centers and parks. It has elementary and middles schools and soon will be home to a high school. Down the road, a shopping center has a 24-hour Harris Teeter, a dentist and dry cleaner.

Emi Nagaki and her husband moved to Stone Ridge with their three sons for more space — a 4,500-square-foot home on Zircon Drive.

About 37 percent of households in the district are made up of married couples with children, according to GMU, with many of them choosing to move from the inner suburbs to outer suburbs.

“It was empty here before,’’ Nagaki said as she played hockey with her 2-year-old son in her driveway. “It was all fields and wildlife.”