The Commonwealth

 is an organisation of scientists that operate from their main base called "The Institute",a place to the north of Washington, D.C.. Little is known about it other than that the people there possess highly advanced technology and technological knowhow. The Commonwealth has created true AI and is capable of creating convincing androids.

Harkness and Dr. Zimmer are from the Commonwealth.

Apperances
 is only mentioned in Fallout 3.