Oldenswort (Danish: Oldensvort) is a municipality in the district of Nordfriesland, in Schleswig-Holstein, Germany, next to the river Eider.

The earliest atheist known by name in modern Europe, Matthias Knutzen, was born here sometime in early 1646.

The founder of German sociology, Ferdinand Tönnies (1855-1936), was born here.

A memorial of him was unveiled in 1990.

This Nordfriesland location article is a stub.