Viana do Castelo, officially known as the City of Viana do Castelo, is a city and municipality located in northern Portugal. It serves as the seat of the district of Viana do Castelo. The city is situated at the mouth of the Lima River and lies along the Portuguese Way path, which is an alternative route of the Camino de Santiago.
As of 2021, the municipality had a population of 85,778 across an area of 319.02 square kilometres. The urbanized area of the city itself contains approximately 36,148 inhabitants, while its extended densely populated region extends into neighboring municipalities such as Caminha and Ponte de Lima.