A large, Federation subspace radio telescope, the array is unmanned, and located on the edge of Federation space along the Cardassian border.
In 2367, the U.S.S. Enterprise-D was sent to the Argus Array to investigate why it had stopped transmitting data. An investigation found that the array's fusion reactors overloaded due to an alien probe.
The probe was later discovered to be Cytherian in origin and benign.