>>886378
Sharp eyes.
In Feb a helper anon had me learn about
wikipedia.org/wiki/Raven_Rock_Mountain_Complex
The Raven Rock Mountain Complex (RRMC) is a U.S. military installation with an underground nuclear bunker near Blue Ridge Summit, Pennsylvania, at Raven Rock Mountain that has been called an "underground Pentagon."[4][5] The bunker has emergency operations centers for the United States Army, Navy, and Air Force. Along with Mount Weather Emergency Operations Center in Virginia and the Cheyenne Mountain Complex in Colorado, it formed the core bunker complexes for the US Continuity of Government plan during the Cold War to survive a nuclear attack.
It's definitely a bunker, one of three main ones.
Blue as in located near the summit of the Blue Ridge Mountains
In a forested area.
Jump thread to >>358133 to read about Site R at the Raven Rock complex.