The ground floor entrance opens into the main foyer; there is also a rear exit
on this level which leads out to the patio then on to the rest of the grounds.
There are numerous surveillance and security system on the first floor (as thereare, to a lesser extent, on the other floors and throughout the estate) to alert the residents to the presence of any visitors or intruders.
The rest of the main floor consists of a lavishly furnished sitting room - used for entertaining important guests and parents,
a formal dining room, an informal lounge, a kitchen - in which meals can be taken when
the dining room is a bit too formal, a library, three large classrooms, a Staff Office, and Professor Xavier's Office.
Although listed as just an Office, inside is also the Professor's Key Computer Terminal, and the mansion's principal terminal to Cerebro.
Until recently the very existence of this room was a secret held by Xavier himself. He used the Ready Room as his own "sanctum sanctorum", a place where he could be alone. But the Ready Room is much more than a glorified study.
From the computer terminal, Professor Xavier can control every system in the Mansion and access files that are for his eyes only. Communication in and out of this room is secured to a hiigher degree than anywhere else in the complex.
Any attack threatening to compromise the terminal's would automatically engage the self-destruct programs.