Where are the Forts, Magazines, Arsenals, dock-Yards, and other needful Buildings?
They are in the Lake Meed National Recreation area which encompasses the area which Bundy’s cattle is grazing upon.
Specifically “dock-yards” and “other needful buildings”:
http://www.nps.gov/lake/planyourvisit/marinas.htm
http://www.nps.gov/lake/planyourvisit/visitorcenters.htm