Virginia state Del. Warren E. Barry, who is retiring from the General Assembly after 14 years, says there are two landmarks in his southern Fairfax County district that any political neophyte will quickly discover:

One is the Lorton prison complex, "which has 3,000 residents who can't vote and the other is Fort Belvoir, which has 12,000 who don't."

Still, there must be something alluring about the district, Barry says, "because there are now seven people fighting for my seat," making the field the largest in any of Fairfax's legislative primaries.

For most candidates in Barry's 42nd House District, Tuesday marks their political debut. None has ever held an elective office, and only one has held a county post.

The four Republicans vying to succeed Barry are:

* J.J. (Jack) Caussin, 48, former county school board member and a social studies teacher at the Holton-Arms School in Bethesda;

* Robert K. Cunningham, 61, a retired Army colonel and project manager for Westinghouse Electric Corp.;

* Bruce L. Green, 35, a vice president for business development with Mount Vernon Realty Inc.;

* William P. Whalen Jr., 39, who owns Reality Realty.

The three Democrats are:

* Lester A. Fettig, 35, former administrator of the office of federal procurement in the Office of Management and Budget;

* Mark L. Glaser, 34, a learning disabilities teacher at Mark Twain Intermediate School, who has made two previous unsuccessful political bids, losing to Barry in last year's election, but getting 38 percent of the vote.

* Lawrence J. Pascal, 41, a senior partner in the Alexandria law firm of Ashcraft and Gerel.

Most of the candidates appear to agree on what Barry calls the two perennial issues in southern Fairfax: security at the District-run Lorton prison and more state transportation money for Northern Virginia.

All three Democrats have spoken out against alcohol and drug abuse and Glaser and Pascal both said they support strong legal action against drunken drivers.

Pascal is the only candidate to declare himself firmly in favor of the Equal Rights Amendment, calling himself a progressive on social issues and moderate to conservative on financial issues. He also favors protecting Fairfax's "physical environment" and Mason Neck in particular.

Barry claims the two-year-old district is largely "moderate-conservative. "There probably are more residents who tend to vote Democratic, especially among the blue-collar families living along Rte. 1 and in apartment complexes near Springfield, but they are not liberal Democrats. I think most are independent and will vote for candidates" on an individual basis.

This apparently is what most of the candidates are appealing to in their literature.

Fettig cites his "whole career of government qualifications, including legislation signed into law by three Presidents." A recent flyer notes that he "was introduced personally by Sen. Lawton Chiles (D-Fla.) . . . . Chiles called Les 'the architect of most of the reform' that's gone on in the government's $150 billion a year contracting business."

Cunningham cites 26 years of "leadership and management with the federal government along with nine years in the private sector" and notes that he is the only "fully retired" candidate who can devote full time to the job. He quotes from a "Dear Bob" letter from Rep. Stan Parris (R-Va.), for whom he worked in last fall's elections.

Caussin claims his job and school board post have given him a "breadth of community experience . . . and knowledge of the people represented."

Glaser says he is "uniquely qualified" as a teacher to address county and state educational issues.

Both Greeen and Whalen claim they are closer to the people. "I am more people-oriented than my opponents," says Green. Whalen says he could help citizens with "personal problems as they relate to government."

Barry feels that Springfield area voters will determine who wins both the primary and the election in the district, which has about 52,000 residents (excluding Lorton prison) and 24,000 voters.

After 14 years representing Springfield and points south, Barry says he is "worn out" and is running this fall for Fairfax County Circuit Court clerk, a post he says has the merit of being up for election only once every eight years.

Barry says he leaves Richmond frustrated, although he was the second-ranking member of the minority party in the House. "That," he says, "made me a second-class citizen in Richmond."