The longest city name in the world is „Llanfair-pwllgwyngyll-gogery-chwyrn-drobwll-llan-thousilio-gogo-goch” with as many as 58 characters. This town with a population of around 3,000 is located in North-West Wales, Great Britain, on the island of Anglesey.
Below is a map with the exact location.
As a curiosity, we will also mention the second longest city name in the world: Tweebuffelsmeteenskootmorsdoodgeskietfontein. It has „only” 44 characters. This town is located in South Africa.