Eldman

From Memory Alpha, the free Star Trek reference

Eldman is a city located in a place that begins with the letters "New."

Gary Mitchell was born in Eldman on stardate 1087.7, and resided there at the street address of 8149. (TOS: "Where No Man Has Gone Before")

This information was listed on Mitchell's personnel file shown on Spock's viewer. It does not list what planet this city is located on.