The Swiss Literary Archives (SLA - Schweizerische Literaturarchiv) in Bern collects literary estates in all four national languages of Switzerland (German, French, Italian and Romansh language). It is part of the Swiss National Library operated by the Federal Office of Culture within the Federal Department of Home Affairs.
The archives were founded in 1991 and are located in the building of the Swiss National Library. The foundation can be tracked back to the last will of the writer Friedrich Dürrenmatt, who died in 1989. Dürrenmatt gave his literary remains to the state, but under the condition that the state establishes a national archive for literature.
The English language version of the website is  - it is also available in French, German and Italian.
More information on the Wikipedia page