A flood of residential development and worsening traffic jams have colored politics this year on Northern Virginia's suburban frontier, leading to spirited races in several contests for the Loudoun County Board of Supervisors.

All eight seats on the county board are up for election Nov. 3. Unlike Fairfax County, Loudoun does not elect a countywide chairman.

Loudoun voters will also decide a referendum over whether to issue $15 million in bonds to buy the Claude Moore property in the eastern part of the county to create a public park.

In at least four board races, aggressive challengers are given an even chance or better to defeat incumbents, raising the prospect of a board taking over in January in which half the faces are new.

Here are the candidates for each seat on the county board:

Blue Ridge: In this western Loudoun district, five-term incumbent James F. Brownell, a former Republican running as an independent, is facing what many see as an uphill battle against Ben F. Fordney, a federal government employe who is required by law to run as an independent but has been endorsed by Democrats. Republican Larry Johnson, who runs a national association of youth vocational clubs, also is running.

The challengers have accused Brownell of lacking the political drive necessary to blunt the tide of suburban growth that has already transformed eastern Loudoun and seems headed west.

Brownell, a farmer who was first elected supervisor in 1967, has been in office longer than Blue Ridge's youngest voters have been alive. Over that time, he has been one of the board's most vocal opponents of rapid growth, but adds that his opponents are ignoring the legal constraints placed on local governments to stop it.

Fordney, the vice mayor of Round Hill, lost a close race to Brownell four years ago. Catoctin: Brownell isn't the only western Loudoun incumbent to be criticized on the growth issue. In the Catoctin District, Democrat Betsey Brown has railed against Republican Supervisor Frank I. Lambert for what she describes as his alliance with progrowth Republicans in eastern Loudoun.

Lambert, a businessman, said he has been unfairly painted as a friend of developers but makes no secret of his aggressive protection of private property rights. The incumbent has been hostile to suggestions of historic preservationists to downzone land around the Village of Waterford.

Brown, a nonpracticing psychiatrist, said saving Loudoun's rural character and protecting the property values of farmers can be accomplished through sensible preservation programs. Dulles: In eastern Loudoun's Dulles District, incumbent Democrat Ann B. Kavanagh is in the midst of a tough campaign against Republican Benjamin H. Hicks Jr. and independent Clements T. (Tom) Berezoski.

Hicks, who works for a Crystal City defense contractor, has accused the incumbent of sacrificing her district's interests in favor of the rural west through her support of exotic land-use measures, such as an unsuccessful transferable development rights proposal two years ago.

Kavanagh, a Fairfax County teacher, has stressed what she describes as her aggressive efforts on the board to ensure that growth does not outpace roads, schools and other public services.

Berezoski, the president of a snow removal agency, has said he expects to spend about $22,000 -- 80 percent of it his own money -- in the race, or more than twice what his opponents plan to spend. His high spending has made Berezoski, who has stressed the need for mass-transportation alternatives, a wild card in the Dulles campaign. Leesburg: In the Leesburg District, incumbent Democrat Charles A. Bos Jr. is facing a tight but genteel contest against Republican Georgia Bange. The candidates have agreed on most major development and transportation issues.

Bos, a veteran Leesburg politician who owns an automobile repair shop, was appointed last year after Supervisor Frank Raflo resigned because of health problems. Bange, a counselor at a Leesburg funeral home, has stressed her collegial style and common-sense approach.

Sterling: In eastern Loudoun's Sterling District, independent Alice G. Bird is waging a long-shot campaign against incumbent Republican Andrew R. Bird III, her ex-husband. Alice Bird, a nurse, has criticized Andrew Bird as being too permissive toward development.

Andrew Bird, who works with a Tysons Corner insurance firm, has been the board's biggest advocate of improving Loudoun's tax base through economic development.

Despite the novelty of ex-spouses becoming political opponents, the Sterling campaign has been absent of personal attacks or salacious revelations. Broad Run: In the Broad Run District of eastern Loudoun, independent Gregory Rex Marquis, an employe of Potomac Electric Power Co., is running an uphill campaign against first-term incumbent Steve W. Stockman, who holds office as an independent but is running as a Republican. Marquis has criticized Stockman as being too close to the development industry; Stockman, a lawyer, has stressed Loudoun's recent strides in attracting economic development. Mercer: In western Loudoun's Mercer District, which includes the Middleburg area, Republican G. Lawrence Moision, a financial consultant, is stressing his fiscal conservatism in a long-shot bid to unseat incumbent Thomas S. Dodson, a Democrat. Dodson, the president of the Northern Virginia Gas Co., is one of the board's most ardent opponents of rapid growth, and has claimed a superior command of land-use issues. Guilford: In the Guilford district of eastern Loudoun, Democrat Betty W. Tatum, the board's current chairman, is unopposed.

Loudoun County, to the north and west of Fairfax County, seems to have one foot in suburban Washington and the other in rural Virginia. Eastern Loudoun is booming, yet the west retains much of the county's old agricultural character.