A Town Portal is a specific spell that opens a portal to the closest Horadrim magical gateway. Most people would need this spell written down on a Scroll to use it, as it's very complicated to learn.
Diablo 3 Town Portal
There will be a lot less Town Portals in Diablo 3, and exactly how they will work is unknown. In the WWI 2008 gameplay video, we saw a Barbarian finding and rescuing Deckard Cain, and he returned back to town through a Town Portal, so it's likely that they will exist in some way. Possibly a lot less common, or with a cooldown. We will know more closer to release.
Background
The Horadrim constructed numerous magical gateways between the mighty fortresses so that they could quickly concentrate their defences against any incursion by the Demons. With but a thought, the Crusaders of the Light could transport themselves to predetermined destinations many leagues apart. Although the secret of creating these gateways has been long lost, it is still possible to use the pathways that are already in place. A Portal opened by means of this spell will always take the caster to the location of the nearest gate and remain open long enough to bring the caster back to his point of origin.
The Church of Tristram is built upon the remains of a Horadrim monastery, and a gateway lies nearby. The same thing is true for several other places in Sanctuary, including cities like Lut Gholein.
 | This article is a stub because a list of Town Portal gateways would be good. Help by expanding it. |