The primary radiation source at the UCSB Center for Terahertz Science and Technology consists of two fully operational FELs, the MM-FEL and the FIR-FEL, covering a wavelength range of 2.5 mm to 63 µm (4 to 160 cm-1 or 120 GHz to 4.75 THz). A third FEL, which is under development and has recently lased for the first time, will extend this to 30 µm. These FELs are connected to a users' laboratory by a vacuum optical transport system. Thirteen switchable output ports allow multiple experimental setups. This facility is unique in providing tunable, coherent, kilowatt-level radiation for scientific research in the far-infrared portion of the spectrum. A 6 MV, recirculating-beam, electrostatic accelerator generates a high quality 2 Amp beam for these FELs which are located in a three position beam switchyard.