A diagram of Darthen
Darthen was a coastal city on the planet Rekag-Seronia.
A map of the city labeled Seronia Quad N2605 depicted landmarks including a doctor, a Federation consulate with a pizza parlor, A Night at the Opera, and a spaceport.
During the 2360s, Darthen had remained neutral throughout the conflict between the Seronians and the Rekags. The city had loyalists from both sides residing there, and as a compromise it was chosen by Ambassador Ves Alkar for the location of a peace conference between the two in 2369. (TNG: "Man Of The People")
The map displayed on the observation lounge monitor was identified as the coastal city of Darthen in the episode script.