Geological Chronicle
Montes Riphaeus is an irregular range of lunar mountains situated along the west-northwestern border of Mare Cognitum and the southeastern margin of Oceanus Procellarum. Trending generally from north-northeast to south-southwest, the range features slender ridge lines with valleys flooded by intruding lava flows.
The feature spans an official extent of 190.12 kilometers across, while its width typically measures between 30 and 50 kilometers. The terrain is bounded by notable surrounding features, including the small but prominent crater Euclides to the west and the crater Lansberg approximately 100 kilometers to the north.
The name originates from the Riphean Mountains of classical antiquity, a range identified in modern geography with the Ural Mountains. Astronomer Johannes Hevelius first introduced the Riphean label to lunar mapping, and Johann Heinrich von Mädler later established the current designation of Montes Riphaeus.