Restrooms are located back and to the right on both 1st and 2nd floors - walk straight back, follow the overhead signs.
The first floor restrooms are located across from the Technical Support Center. To get to the restroom, enter through the lobby of the library and head towards the back of the library. When you seen The Commons (the large room with windows), make a right and head down the hall and the restrooms will be on your right.
The second floor restrooms are located across from the Archives.
