The ideas of government bunkers may have made some sense in the 1950s when land based ballistic missiles were the primary threat.
Off shore submarines can hit the mainland US within a few minutes—no leadership would make it outside of DC—and they would never be able to poke their heads out of any underground shelters.
The old plans included flying leadership to a bunker in West Virginia—that would never work these days.
One of the places USG employees will be sent to is located along the Application Trail, the first road outside the shenandoah national park north of the AT in the park; this bomb shelter is easily identified by the old buildings and thousand meter chainlink fence keeping the AT just to the left of the creek and right of the fence. You literally walk about one mile along this fence. However, the site is located at southern permeniter of the fence;)
About 10 years ago, the USG actually moved HQ elements from DC agencies to this spot but they were not aware where they went too.
I stayed at hostel located to right a quarter mile walk. I was hiking S.Bound that trip on the AT.
The small town of Culpeper nearby, as well as Beltsville MD are good locations to find an official government center for shelter.