During my time at NRAO, they operated the four telescopes shown here for the National Science Foundation. As of October 2018, a reorganization placed the GBT and VLBA under a different name. I do not know what the long-term plans are for the organization.
The Very Long Baseline Array, or VLBA, is a network of 10 25 meter antennae spread across the United States and functioning as a single telescope.
The Very Large Array, or VLA, is a network of 28 25 meter antennae located in central New Mexico.
The Atacama Large Millimeter Array, or ALMA, is an array of 66 12m & 8m antennae located high in the mountains of Chile.
The Greenbank Telescope, or GBT, is a single 100m x 110m telescope located in the National Radio Quite Zone, West Virginia.