Ahmedeen was a planet with seas of liquid argon. This planet was located somewhere in the Milky Way Galaxy.
After biomimetic copies of Tom Paris and B'Elanna Torres were married aboard the duplicate USS Voyager in 2375, Neelix suggested a holoprogram of wind surfing on Ahmedeen for their honeymoon. (VOY: "Course: Oblivion")
This planet was only mentioned in dialogue.
The Star Trek Encyclopedia, 4th ed., vol. 1, p. 13 locates this planet in the Delta Quadrant.