The largest city on Rychri was Matalia.
An automated distress call was issued in that same year. Upon arrival, the USS Prospect accessed an orbiting sensor platform to find all the inhabitants had disappeared from the surface within the period of a half-hour. (Star Trek: The Prospect Chronicles: "Honor Thy Father")
Matalia was the largest city on Rychri.
In 2367, two away teams, led by Commander Hahn Jun-Seok, beamed down from the USS Prospect to Matalia to determine where the Rychrima population had disappeared to. (Star Trek: The Prospect Chronicles: "Honor Thy Father")