It's the National Archives in D.C.; it's a secured room especially for the 9-11 Commission; it's a big glass building, so I am assuming it's the one outside D.C. (Bethesda?)
I'm confused about what files of Clinton's are in D.C. and what's in Little Rock; certainly they wouldn't have shipped documents BACK to D.C.
College Park Md.
http://www.archives.gov/welcome/index.html