More than 600 acres of the former Army base at Ballykelly has been placed on the open market in the hope of attracting a private sector buyer.
Lambert Smith Hampton has been appointed by the Office of the First and Deputy First Minister (OFMDFM) for the vast expanse of land which contains buildings and hangars.
This is the second attempt to attract an investor from the private sector.
The first failed effort to sell the site in 2011 attracted a top bid of only £1.5m - far below the value of the available land. Since then nine acres have been allotted for the relocation of the Department of Agriculture and another slice has gone to Northern Ireland Water.
However, OFMDFM is keen to offload the rest of the site as Stormont currently pays out a whopping £100,000 a year in security and maintenance alone.
In November 2013 a market testing exercise to gauge interest in the site from the private sector was carried out by an estate agency.
It reported a "significant" interest from commercial, agricultural, leisure and community sectors, which is understood to have led to the new sale.
First Minister Peter Robinson and Deputy First Minister Martin McGuinness described the former barracks as a "massive investment opportunity".