Hangar E

From the outside, Hangar E looks like any other unassuming hangar on the nondescript Nevada military base it's part of. Inside is a different story, with hi-tech computer systems mixed with alien technology, for it is the home base of the Autobots.

Prime cartoon
Agent Fowler made use of the office in Hangar E after the destruction of the silo the Autobots had been using as a base. Following the destruction of Darkmount, the Autobots moved in to Hangar E. They installed the GroundBridge salvaged from the derelict Harbinger, and other equipment salvaged from the ruins of their old base, though not without Wheeljack damaging the building by throwing a lobbing ball at Bulkhead.

Soundwave was taken there after he was captured, as it was shielded against all transmissions. The Decepticons soon learned of its location when Laserbeak tailed Fowler back there and freed Soundwave. Starscream and a squad of Vehicons attacked the base, leveling the hangar marked 'E' with missiles. Luckily the letters on the buildings had been modified, and the base's mess hall was destroyed instead of the real Hangar E.

2015 Robots in Disguise cartoon
Sometime after Team Prime left Earth, Hangar E and the surrounding base was abandoned. Bumblebee led his unit there to reminisce about the good ol' days for a bit before they moved on.