What is the name of the facility where Portal takes place?

The facility where Portal takes place is the Aperture Science Enrichment Center. Chell awakens inside this enormous research and testing complex, where the artificial intelligence GLaDOS guides her through a sequence of experiments using the Aperture Science Handheld Portal Device, commonly called the portal gun.

Aperture Science began as a company founded by Cave Johnson in 1943. It originally made shower curtains for the U.S. military before becoming an increasingly eccentric research organization. Its experiments eventually included portal technology, artificial intelligence, neurotoxin, turrets, and experimental gels. By the time of Portal, the Enrichment Center appears largely abandoned, yet its automated systems remain active.

The full name is sometimes given as the Aperture Science Computer-Aided Enrichment Center. This should not be confused with Black Mesa, the research facility from the Half-Life series. Portal shares the Half-Life universe, but Chell's tests occur at Aperture. Portal 2 later reveals much more of the facility, including older underground laboratories built during Cave Johnson's earlier research programs.