Lake Arpi (Armenian: Արփի լիճ) is located in the Shirak Province of Armenia, in the northwestern part of the country. The lake level is at an altitude of 2,023 m. The lake area is 22 square kilometres. The area was increased artificially in the 1950s from the natural state of 4.5 square kilometres, and the lake has become the second most important water body of Armenia, next to Lake Sevan. It is used for irrigation and hydropower production.