Fairfax County, along with Elm Street Development and Alexander Cos., broke ground Tuesday on a mixed-use village at the site of the former Lorton prison in the southeastern part of the county.

The developers plan 350 residential units, 62,335 square feet of retail and office space at the project known as Liberty Crest at Laurel Hill.

The commercial real estate firm Colliers International said the first phase of the retail leasing effort is a 48,000-square-foot new building on Silverbrook Road. Efforts are focused on signing an anchor grocery tenant, after which Colliers said it would seek neighborhood retail to occupy additional space.

“Liberty Crest will serve the daily shopping needs of a part of Fairfax County that is starved for a grocery store, as well as other retail. The site offers retailers a unique opportunity to locate in a historic site in the renowned Lorton area,” Bob Browning, a vice president at Colliers International, said in a statement. He is leading the retail leasing team for Elm Street Development.

The project is located about a mile from I-95.

Fairfax County purchased the former Lorton Reformatory after the last prisoner was transferred in 2001.  Since then, according to the county’s Website, the historic buildings and surrounding 2,300 acres of rolling hills and wooded stream valleys have been redeveloped into the Laurel Hill community, complete with new schools, parkland, a golf course, and an arts center.

The public/private mixed-use project is a final piece of the development. The Lorton site is listed on the National Register of Historic Places.