Plainfeld is a municipality in the district of Salzburg-Umgebung, in the state of Salzburg, Austria. It lies in the federal state of Salzburg in the west-central part of the country.
As a municipality within Salzburg-Umgebung, Plainfeld belongs to the administrative district that surrounds the city of Salzburg. The district's seat is the city of Salzburg itself, though the city is administered separately from the district.
Plainfeld is one of the smaller communities in the Salzburg-Umgebung district, situated in the Alpine foothills region of the state of Salzburg.