Virginia corrections officials are considering a county midway between Richmond and Washington as the site for a giant 2,400-bed prison, a move hailed by many as proof that Gov. Charles S. Robb has abandoned earlier proposals for a prison in Fairfax County.

Robb was investigating purchase of land at Fort Belvoir in southern Fairfax when the prison proposal suddenly became a highly charged campaign issue in last fall's 8th District congressional race. In an attempt to quell the political storm and spare his Democratic allies, Robb announced he was withdrawing the request to buy the 107-acre Army tract of land. But at the time, Robb would not rule out building a prison in Northern Virginia.

This week, state prison officials shifted their search for a prison site to rural Caroline County in the middle of the state's urban corridor. George Stoddart, Robb's press secretary, declared the Fort Belvoir proposal "officially and finally dead."

Caroline County officials are scheduled to meet with representatives of the state Corrections Department tomorrow for talks on Corrections Director Raymond Procunier's suggestion for placing in the county a large prison that could resolve Virginia's prison crowding problem for many years.

"This is an informational and fact-finding period for us," said corrections spokesman Gilbert Miller. "We are not ready to roll out the bulldozers or anything like that."

The state's interest in Caroline County was greeted by Northern Virginians this week as a sign that plans for a facility in the Washington suburbs have been dropped. "As we understand it, the Caroline County prison is a replacement for the Northern Virginia prison the governor proposed putting in Fairfax," said an aide to Rep. Stanford E. Parris (R-Va.) who had attacked the Fort Belvoir plan last October. "We consider that a victory for the people of Fairfax."

"I'm absolutely delighted," said Fairfax Supervisor Sandra Duckworth, who represents the area around Fort Belvoir. "I don't know whether this Caroline has the potential of taking the place of the other idea, but certainly, I'm hopeful it will take the pressure off Northern Virginia."

Robb and Procunier have emphasized putting prisons close to population centers so prisoners can be more accessible to their family, friends and job-training facilities. There are no major prisons in Virginia's northern tier, even though the region accounts for 15 percent of the state's prison population.

Several years ago, Virginia embarked on an ambitious prison building program with plans for five new 500-to-750 bed facilities to be built by the end of this decade. Of those, two -- one in Brunswick County and another in Buckingham -- are finished and money for two more -- in Augusta and Nottoway counties -- is in the state's budget.

No site has been selected for the fifth new prison, although officials in Alleghany County on the West Virginia border have expressed an interest in securing the prison.