Warrenton became the sixth Virginia locality yesterday to abandon its at-large system of electing local officials -- a procedure that civil rights advocates say has prevented blacks from winning office in numerous towns in the state.

Officials from Warrenton agreed to adopt a ward system for Town Council elections, settling a lawsuit filed by a group of blacks and the American Civil Liberties Union.

"It's a complete rout," said Victor Glasberg of Alexandria, attorney for the plaintiffs. Officials of the Fauquier County town agreed to "precisely what the ACLU asked them last September" before the suit was filed, Glasberg said.

"I don't think we had much choice," said Town Council member J. Frederick Austin Jr. He was alluding to comments by U.S. District Judge Robert R. Merhige, who made clear after the first day of testimony in the lawsuit that he wanted the issue settled out of court.

Although blacks compose about 20 percent of Warrenton's 4,000 residents and 12 percent of its voters, no black has been elected to local office. Lawyers for the town had resisted the lawsuit, one of a number filed by the ACLU against Virginia localities, arguing that blacks lost elections because they had failed to organize.

As a result of ACLU action, Farmville, Prince Edward County, Halifax, Hopewell and Blackstone ended at-large elections.

Glasberg said details of the Warrenton settlement, which the two sides reached in Alexandria within 15 minutes Monday night, must be submitted to Merhige in 30 days.

Town officials promised to create five wards, one containing a majority of blacks, for elections for the seven-member Town Council. Two council members will continue to be elected at large.

Warrenton's May 6 elections will take place on the at-large system, but a special election under the new system must take place within a year.

Several black residents of Warrenton testified they were frustrated by the current system. Some former candidates for office said they had not renewed attempts to run because they felt they could not win.

Political scientist Gordon Henderson of Richmond, Ind., testified that white town officials were ignorant of the income gap between blacks and whites in Warrenton, where black per capita income is $4,986 and white income is $8,330. As a result, he said, blacks have felt "left out" by the town government.

Council member Austin said he did not believe the change would have any long-range impact because "there is no racial discrimination in Warrenton."

A "small group" of blacks brought the suit because "they feel discouraged . . .[they] feel like they are disenfranchised," Austin said. "It is important what people feel is true . . . . We have to respond to that, even though we are blameless."