The Laser Interferometer Gravitational-Wave Observatories are located in Hanford and Livingston.
LIGO’s mission is to open the field of gravitational-wave astrophysics through the direct detection of gravitational waves. LIGO detectors use laser interferometry to measure the distortions in space-time between stationary hanging masses caused by passing gravitational waves. LIGO is a national facility for gravitational-wave research, providing opportunities for the broader scientific community to participate in detector development, observations and data analysis.
On September 14, 2015 gravitational waves were detected for the first time by both of the twin Laser Interferometer Gravitational-wave Observatory (LIGO) detectors.