Gateway

From Memory Alpha, the free Star Trek reference.

You may also be looking for the article on the Iconian gateways, or the DC TNG comic of the same name.

Gateway was a site on the planet Vulcan which led into the Forge. It was believed to be the area where Surak began his pilgrimage into the Forge.

Jonathan Archer and T'Pol traversed Gateway in 2154 when beginning their journey into the Forge in search of the Syrrannites. (ENT: "The Forge")