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- Oravais – consolidated with Vörå-Maxmo to form Vörå in 2011
- Oulujoki – was divided in 1965. Most of it was consolidated with Oulu, and other parts with Haukipudas, Kempele, Kiiminki, Oulunsalo, Tyrnävä, Utajärvi and Ylikiiminki.
- Oulunkylä – became part of the City of Helsinki in 1946
Read more about this topic: Former Municipalities Of Finland