Holberg 917G was a small planet in the Omega system. This system was located in the Alpha Quadrant. This planet had two moons. This planet was home to a large quantity of natural ryetalyn.
In 2239, the planet was purchased by a private concern, a gentleman named Mr. Brack. This was later revealed to be one of many aliases of the planet's only inhabitant, Flint the immortal, when the Federation starship USS Enterprise visited in 2269. (TOS: "Requiem for Methuselah")
Holberg 917's location in the Milky Way Galaxy was depicted on a Federation star chart in 2293. (Star Trek VI: The Undiscovered Country, production art)
The location of Holberg 917G on "The Explored Galaxy" star chart
Flint's home on Holberg 917G, as it appeared in the original episode