The Center is a secret facility located in Tucson, Arizona with ties to the Dollhouse that very few people, even Dollhouse employees, know about.
After killing the real Steven Kepler and dumping his body in Tucson, Alpha sent a picture of the Paul Bunyan statue to Laurence Dominic. This was done to distract the L.A. Dollhouse staff, as he was well aware that Dominic would know his supposed intentions in Tucson. The distraction later allowed Alpha to infiltrate the L.A. Dollhouse, and kidnap Echo and steal her past imprint wedges. (S1: "Briar Rose", "Omega")
The Center is surrounded by a shroud of secrecy, with only a select few knowing of its existence and location, while other employees, such as Topher Brink kept ignorant of its existence. (S1: "Briar Rose")