Finland’s place names range from those of unknown or unrecognizable origins to more clearly derivable onomastics.
There are both national and international recommendations on how to use the bilingual country's place names in texts written in different languages.
A few notable place names such as a few major hydronyms Päijänne, Saimaa, Imatra and Keitele which are thought to be among the oldest toponyms still lack a sound derivation from existing languages despite different approaches.
[3] Other substrata in Finland’s toponyms include Finnic, Baltic, Germanic and Slavic linguistic influence in several chronological layers.
[4] In bilingual municipalities, the Language Act requires that all toponyms have both a Finnish and a Swedish name.
[4] In addition, many monolingually Finnish municipalities have an official Swedish name, and vice versa.
The municipalities have the power to decide their own name but they are required to consult with the Research Institute for the Languages of Finland before the official decision.
These may fall under the category of "already established place names in foreign languages" mentioned in the above recommendations.
As all municipalities in the Finnish capital region, which is the most swiftly developing area in Finland, are bilingual, the problem of devising good toponyms is not a small task.
The rest receive internal locative suffixes, as in Helsingissä (being inflected form of the town, meaning: in Helsinki).