Fairfax County's population boom of the 1980s is giving the Board of Supervisors a political migraine as they enter the 1990s.

Board members say they will have to add up to two new seats to the board after they receive data from the 1990 census, or else redraw the county's current eight districts so wildly that they would bear little resemblance to the present ones. The county's population was 596,901 in 1980 and is projected to be 795,703 this year.

Results from the 1990 census will force political boundary changes for all levels of government across the country. Officials from suburban Maryland and Virginia, for instance, hope the population booms they experienced in the 1980s will result in each area getting a new seat in Congress and additional legislative seats in Annapolis and Richmond.

While all of those changes are likely to spawn endless horse-trading among officials hoping to maintain safe elective districts, the process is likely to be particularly messy in Fairfax, board members say.

Because of rapid growth, one supervisor in the county's booming western suburbs -- Elaine N. McConnell (R-Springfield) -- represents more than twice as many residents as other supervisors in the county's older neighborhoods inside the Capital Beltway. Under any redrawing that would equalize the districts, some supervisors, therefore, will lose thousands of their present constituents.

Supervisor Martha V. Pennino (D-Centreville), whose district will have to shrink dramatically under any scenario, said, "Every time we redistrict, I really feel like I've been invited to a party and I'm the turkey and they're carving me up."

Pennino said the board should consider adding two seats in western Fairfax, which would raise the board to 11 members, including a chairman who is elected countywide. The strategy would minimize the need to redraw the existing districts.

Supervisor Joseph Alexander (D-Lee), whose district would be drastically changed without adding new districts, said he also supports adding two seats to the board. "If we keep the same eight districts, then we'd have to do all kinds of moving of boundaries and I think that would be very disruptive."

The two most important goals for supervisors during the redistricting process are to ensure that they remain in their own district and that another incumbent supervisor is not moved to their district. After that, the main challenge is to get rid of precincts that vote with the opposing party and pick up friendly precincts from neighboring supervisors.

The process is one of the most fundamental in politics, but it can also be one of the most painful and dangerous, the political equivalent of publicly saying which children you like the most and then giving the other ones away.

"No one wants to be quoted saying, 'I want to get rid of Podunk' or 'If you give me that {precinct}, I'm dead,' " said state Sen. Joseph V. Gartlan (D-Mount Vernon), chairman of the Senate's Privileges and Elections Committee, which will play a major role in redrawing state legislative and congressional districts.

The last time the Fairfax board went through the exercise -- after the 1980 census -- it proved so difficult that the supervisors were able to agree on how to carve up the county only after an illegal secret meeting in the office of Audrey Moore, the current board chairman who then represented the Annandale District.

The supervisors toasted their accomplishment with champagne at the meeting, but later were found guilty of violating the Virginia Freedom of Information Act.

The problem, according to Supervisor Thomas M. Davis III (R-Davis), was that "last time, too many interlocking commitments had already been made . . . . We had to get into a room and do it or we'd still be there voting."