WASHINGTON ( CNN ) -- Washington notables broke ground on the future home of the Department of Homeland Security on Wednesday , symbolically starting construction on the biggest federal building project in the Washington area since the Pentagon 68 years ago . Rendering of future Coast Guard headquarters , with green roof designed to capture and reuse water . The project will bring together more than 15,000 employees now scattered in 35 offices in the region , placing them on a 176-acre campus strewn with historic buildings in a long-neglected corner of Washington , five miles from the Capitol building . Department leaders hope the $ 3.4 billion consolidation will help the department fulfill its core mission -- protecting the homeland -- in ways big and small . `` It will help us hold meetings , '' Secretary Janet Napolitano said . `` It will help us build that culture of 'One DHS . ' '' At the groundbreaking , political leaders shoveled dirt with care , but pitched historical references and metaphors with abandon . `` I do have a kind of paternalistic feeling towards DHS , '' said Sen. Joe Lieberman , I-Connecticut , an early advocate for creating the department . `` I feel like we 've finally given a home to this child we 've created , which is finally reaching maturity . '' Lieberman likened the creation of the department 's headquarters to the creation of the Pentagon . Ground was broken on the Pentagon on September 11 , 1941 , exactly 60 years before the 2001 terrorist attacks , he noted . President Franklin Roosevelt planned the defense consolidation , Lieberman said , because he knew war was imminent and felt it could be coordinated more efficiently from one location . The Department of Homeland Security also will benefit by consolidation , Lieberman said . The site today has the appearance of a sprawling college campus -- although one stuck in time . Established by Congress in 1855 as the Government Hospital for the Insane and later renamed St. Elizabeths , the campus has 62 buildings built between the 1850s and 1940 . The federal government plans to preserve 52 of the historic buildings , which are in varying stages of decay . Of the 10 buildings to be destroyed , eight are greenhouses that have major structural damage . Some $ 650 million in Department of Homeland Security and General Services Administration federal stimulus money is expediting some of the rehabilitation , the latter agency said . The project also includes large amounts of new construction . The first building , a 1.8 million-square-foot U.S. Coast Guard headquarters , will cost about $ 435 million and is scheduled for completion in 2013 . The building will include `` green roofs '' and landscaped courtyards to capture and reuse surface water . Former Homeland Security Adviser Fran Townsend said the department is right to consolidate its facilities but cautioned it wo n't make the huge differences some people claim it will . `` For one thing , what we know is St. Elizabeths is not big enough to hold all of their headquarters components , '' she said . And while the department needs to be far enough away from downtown Washington to survive an attack , it `` suffers from not having a presence on the National Mall just like all the other major agencies , '' she said . City officials were ebullient Wednesday about the prospect of a blighted area being transformed . The gated campus borders some of Washington 's most violent streets . `` They 're going to try us , and they 're going to like us , '' said Eleanor Holmes Norton , the District of Columbia 's delegate to Congress . Councilman Marion Barry , who has long complained the area is ignored by the federal government , tweaked visitors at the groundbreaking . `` I hope most of you had your GPS 's working , '' he said .
It 's biggest federal building project in Washington area since Pentagon 1940 . Complex to be on campus of historic buildings in long-neglected part of Coast Guard to gather 35 employees now scattered in 35 offices . First new building : D.C. Project headquarters , costing about $ 435 million .