Hainfeld is a municipality in the district of Lilienfeld, in the Austrian state of Lower Austria. It lies in the eastern part of Austria, within the federal province of Lower Austria, and is administered as part of the Lilienfeld district.
The town is situated in the foothills of the Lower Austrian Alps, in a landscape of forested hills and valleys typical of the region. It is one of several small municipalities that make up the district of Lilienfeld, an area known for its rural character and its proximity to the Wienerwald and the Alpine foothills.
Like many towns in this part of Lower Austria, Hainfeld functions as a local administrative and service centre for the surrounding countryside. Its position within the Lilienfeld district places it within reach of the larger towns of the region, including the district seat of Lilienfeld itself, while remaining a distinct and separate municipality in its own right.