Fail was a Portuguese parish in the municipality of Viseu, with 6.92 km2 (2.7 sq mi) and 664 inhabitants (2011). Density: 96 inhabitants / km2 (245/sq mi).

In 2013 Law No 11-A / 2013 was changed and Fail was reclassified into the Union of Parishes Fail e Vila Chã de Sá [pt] based in Vila Chã de Sá [pt].

Coordinates: 40°36′28″N 7°58′37″W / 40.6078636°N 7.9770136°W / 40.6078636; -7.9770136