Filzbach is a former municipality in the Canton of Glarus in Switzerland . Effective from 1 January 2011, Filzbach is part of the municipality of Glarus Nord .

Filzbach is first mentioned in 1394 as Vilentzspach.

Filzbach has an area, as of 2006, of 13.9 km2 (5.4 sq mi). Of this area, 35.4% is used for agricultural purposes, while 40.9% is forested. Of the rest of the land, 4.6% is settled (buildings or roads) and the remainder (19.1%) is non-productive (rivers, glaciers or mountains).