Santo Tirso is a city and municipality located in the north of Porto Metropolitan Area, 25 km from central Porto, Portugal. In the region, t…Santo Tirso is a city and municipality located in the north of Porto Metropolitan Area, 25 km from central Porto, Portugal. In the region, the Ave Valley, there is a large center of textile industry. The population in 2021 was 67,709, in an area of 136.60 square kilometres.