CENTREVILLE, Va. -- In this affluent suburb of Washington, D.C., "hagwons" are as common as Starbucks.

Young Koreans fill the storefront after-school centers every day, cramming for their Advanced Placement exams and SATs, and striving for the academic opportunities and financial security that pulled their parents from the other side of the world.

"They want to be successful and make money," said John Hong, 17, as he exited a Subway that shares a shopping plaza with a hagwon called Score. "That's why they came to this country -- to make money."

This is the childhood home of Cho Seung-Hui, the gunman in Monday's devastating shooting at Virginia Tech. It's also at the heart of one of the fastest growing regions in the country, fueled by immigrants in search of the American dream.

From 2000 to 2005, Virginia's northern counties grew by 13 percent, adding more than 290,000 residents, according to the University of Virginia's Weldon Cooper Center. Jobs in defense, technology, construction and government have attracted new arrivals from across the country and the globe.

Fairfax County, with 1 million residents, is home to some of the top public schools in the country, with more 90 percent of its high school graduates going on for higher education. In 2005, more than 11,600 took AP exams. More than 17 percent of the students in the county's schools are Asian, according to district figures.

"Everybody has to play an instrument. Everybody has to be in a society. Everybody has to take an AP class," said Jenet Ahn, who owns a dry cleaning shop in Centreville.

Her store is a half-mile from Truitt Farm Drive, the quiet cul-de-sac where Mr. Cho's parents live in a white, two-story house.

Yesterday, the road was blocked by traffic cones, and a police cruiser guarded the house. School safety police limited access to nearby Stone Middle School, where two of Mrs. Ahn's children are students, and Westfield High School, where Mr. Cho graduated in 2003.

Two of the Virginia Tech victims, Erin Peterson and Reema Samaha, were Westfield graduates.

"You know that Westfield is an outstanding school where our students benefit from a world-class learning environment. We are strong. We are safe and secure," Tim Thomas, the principal, told reporters in the parking lot of the school's 159-acre campus.

School officials have asked the news media not to interview students at the school.

"Please understand that we are in the process of both recovery and grief," Mr. Thomas said.

Centreville's Korean community has boomed in recent years. Some migrants have moved from heavily-Asian areas inside the Washington beltway, in search of cheaper housing and better schools. They are bringing a range of businesses, from delis to technology firms.

The Korean Central Presbyterian Church, based in nearby Vienna, is building a "mega-church" in Centreville.

Many are eager to welcome the newcomers.

"It's a community where we're trying to make inroads," said Eileen Curtis, president and chief executive officer of the Dulles Regional Chamber of Commerce. "We have made a few overtures."

Mr. Cho's shooting rampage shocked everyone in Centreville, where Virginia Tech car decals are ubiquitous. But many recent Korean immigrants see the incident on a very personal level.

"We feel like this is one community," said Daniel Lee, senior pastor at the All Nations Dream Church in Annandale, which last night held a prayer service in honor of the Virginia Tech victims. "We are building on something here. It's hard. It takes a lot of time to build something up and just a little bit of time to break it down."