We present two low-noise amplifiers for the frequency range of 160 to 270 GHz. The amplifiers were fabricated using a 35-nm InP HEMT technology and designed for room temperature and cryogenic operation. A four-stage amplifier in a common-source topology and a three-stage amplifier utilizing a cascode stage at the output achieve 15 to 25-dB on-wafer measured gain from 160 to 270 GHz. When packaged in WR5 waveguide housings the amplifiers exhibit room temperature measured noise of 600 to 760 K from 160 to 220 GHz. When cryogenically cooled the three-stage amplifier shows a noise of 80 to 115 K over the range of 164 to 220 GHz. Furthermore, our initial room temperature measurements show a noise figure of 7-8 dB over the 220 to 252 GHz range for a four-stage amplifier packaged in a WR3 waveguide housing.