The district of Viana do Castelo (Portuguese pronunciation: [viˈɐnɐ ðu kɐʃˈtɛlu], Portuguese: Distrito de Viana do Castelo) is a district located in the northwest of Portugal, bordered by Spain from the north and Braga District from the south. It has an area of 2,255 km² and a population of 252,011 (2006), for a density of 111.8 inhabitants/km². The district capital is the city of Viana do Castelo.
The district is composed of 10 municipalities:
Viana do Castelo (Portuguese pronunciation: [viˈɐnɐ ðu kɐʃˈtɛlu]) is a municipality and seat of the Viana do Castelo District in the Norte Region of Portugal. The city proper has 36,148 (INE, 2001) inhabitants and the municipality has a total population of 91,238 inhabitants (2006) over a total area of 318.6 km².
It is located at the mouth of the Lima River.