A federal jury in Alexandria awarded $210,000 yesterday to about 7,000 prisoners held between August 1980 and last January in the Prince William County jail, which the jurors earlier had found unconstitutionally overcrowded.

The verdict, only the third such jury award arising from a prisoner class-action suit in the country, will be divided between convicted felons awaiting transfer to state prisons at the time and pretrial detainees.

"It could have been more, but it's okay," said Vic Glasberg, one of two American Civil Liberties Union lawyers representing the prisoners.

Assistant county attorney John Foote said a decision on whether to appeal the verdict will be up to the Prince William supervisors. The award was less than the county had expected, Foote said. One lawyer familiar with the case said a $750,000 out-of-court settlement offer had been rejected by the supervisors.

The same six-member jury found the jail to be in violation of constitutional standards in early April after hearing testimony by experts that the aging, red brick structure in Manassas was perhaps the worst jail in the state. The prison lacked adequate space, medical care, security and other safeguards and at times exceeded its prisoner capacity by 400 percent, several witnesses said.

Yesterday's award gives $170,000 to pretrial detainees and $40,000 to convicted felons. District Judge Richard L. Williams said he assumed the disparity was because a majority of the prisoners were in the pretrial category and "subjected to these conditions while they were basking in the glow of innocence."

A new $5 million detention center opened within days of the April verdict. Judge Williams is expected soon to issue a permanent injunction enjoining the county from ever using the old jail to house prisoners or others involuntarily without a specific court order.

Prince William has filed its own claim against Virginia state corrections officials, arguing that a chronic backlog of prisoners waiting to enter the state prison system contributed to local overcrowding.