Town

Desktop/Console/Mobile-Only Content: This information applies only to the Desktop, Console, and Mobile versions of Terraria.

A town is a player-created mini-biome which is created when three or more NPCs are in close proximity (including the Old Man, Traveling Merchant, and town pets, but excluding the Skeleton Merchant). Towns have the greatest effect on reducing the spawn of enemies^[1], and have unique music tracks for both day and night^[2]. However, the enemy spawn reduction effect is weaker in the Underworld, and will not have effect when some events are occurring. See Notes for a detailed list.

Notes

Only NPCs that are within a 240×135-tile rectangle centered on the player are considered inhabitants of the town.^[3]
The enemy spawn reduction effect a town provides will not have effect in any of the following circumstances^[4]:
- Any of the following events is occurring: Blood Moon, Pumpkin Moon, Frost Moon, and Solar Eclipse.
- Any of the following events is occurring while the player is on or above surface: Goblin Army, Pirate Invasion, Frost Legion, and Martian Madness(Desktop, Console and Mobile versions).
- The player is in range of the Old One's Army event.
- The player is in the Corruption, Crimson, Dungeon, or Meteorite biome.
- The player is in range of any Celestial Pillars.
Despite a town has to include no less than 3 NPCs, pylons only require two NPCs (including the Old Man and town pets, but excluding the Skeleton Merchant and the Traveling Merchant) to function.
Due to NPCs being present while in a town, critters have increased spawn rates.

A town in the Jungle with 3 NPCs living in it: the Witch Doctor, the Dryad, and the Painter.

↑ Information taken from the Desktop 1.4.3.6 source code, method SpawnNPC() in Terraria.NPC.cs. There may be inaccuracies, as the current Desktop version is 1.4.4.9.
↑ Information taken from the Desktop 1.4.3.6 source code, method UpdateAudio_DecideOnNewMusic() in Terraria.Main.cs. There may be inaccuracies, as the current Desktop version is 1.4.4.9.
↑ Information taken from the Desktop 1.4.3.6 source code, method AddIntoPlayersTownNPCSlots() in Terraria.NPC.cs. There may be inaccuracies, as the current Desktop version is 1.4.4.9.
↑ Information taken from the Desktop 1.4.3.6 source code, method SpawnNPC() in Terraria.NPC.cs. There may be inaccuracies, as the current Desktop version is 1.4.4.9.