4,505 (31 Dec 2006)
Ruukki is a former municipality of Finland.
It is located in the province of Oulu and is part of the Northern Ostrobothnia region. The municipality had a population of 4,505 (31 December 2006) and covered an area of 772.58 square kilometres (298.29 sq mi) of which 5.79 km2 (2.24 sq mi) is water. The population density was 5.88 inhabitants per square kilometre (15.2/sq mi).
The municipality was unilingually Finnish.
In 2007 municipality of Ruukki joined together with Siikajoki.