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- Jaakkima – was lost to the USSR in 1944
- Jaala – consolidated with Kouvola in 2009
- Jeppo – consolidated with Nykarleby in 1975
- Johannes – was lost to the USSR in 1944
- Joutseno – consolidated with Lappeenranta in 2009
- Jurva – consolidated with Kurikka in 2009
- Jyväskylän maalaiskunta – consolidated with Jyväskylä in 2009
- Jämsänkoski – consolidated with Jämsä in 2009
- Jäppilä – became part of Pieksänmaa in 2004, along with Pieksämäen maalaiskunta and Virtasalmi
- Jääski – was partially lost to the USSR in 1944, the rest of the municipality was incorporated into Imatra, Joutseno and Ruokolahti in 1948
Read more about this topic: Former Municipalities Of Finland