What is the name of the planet where Data was created?

The planet where Data was created is Omicron Theta. It was the site of the Soong family’s android research and the colony where Dr. Noonien Soong built Data and his android brother Lore.

Omicron Theta is introduced in the first-season episode “Datalore,” when the Enterprise-D visits the abandoned colony while investigating Data’s origins. The crew discovers Lore, an android with Data’s appearance, and learns more about the experiments that produced the Soong-type androids.

The colony was destroyed by the Crystalline Entity, which consumed the life-forms there. Data survived because he had been deactivated and was later discovered and reactivated by the USS Tripoli. Omicron Theta is therefore both Data’s place of creation and the location of the catastrophe that erased his original human community. The common mix-up is with Vulcan or Betazed, important Star Trek worlds that are unrelated to Data’s construction.