It became the capital of the Linth valley in 1419. In the 18th and 19th centuries, the valley began to be industrialized.

In 1864, the first European labor law to protect workers was introduced in Glarus, prohibiting requiring workers to work more than 12 hours a day.

The arms, were adopted in 1939, but are nuch older, show an ibex. The arms are derived from the arms of the Knights of Glarus and were already used by Johannes I von Glarus in 1299. The family later (15^th century) settled in Zürich, but the city had already adopted the ibex as its arms. The meaning of the colours is not known.