Which city is the largest city in the province of Biscay?

Bilbao is a city in northern Spain, the largest city in the province of Biscay and in the Basque Country as a whole. It is also the largest city proper in northern Spain. Bilbao is the tenth-largest city in Spain, with a population of 345,141 as of 2015. The Bilbao metropolitan area has 1,037,847 inhabitants, making it one of the most populous metropolitan areas in northern Spain; with a population of 875,552, the comarca of Greater Bilbao is the fifth-largest urban area in Spain. Bilbao is also the main urban area in what is defined as the Greater Basque region.

Bilbao is situated in the north-central part of Spain, some 16 kilometres (10 mi) south of the Bay of Biscay, where the economic social development is located, where the estuary of Bilbao is formed. Its main urban core is surrounded by two small mountain ranges with an average elevation of 400 metres (1,300 ft). Its climate is shaped by the Bay of Biscay low-pressure systems and mild air, moderating summer temperatures by Iberian standards, with low sunshine and high rainfall. The annual temperature range is low for its latitude.