The first element is the plural genitive case of eið which means "isthmus" or in this situation, a "path between two lakes".

On 3 November 1917, a royal resolution changed the spelling of the name of the municipality to Eidskog, removing the definite form ending -en.

The official blazon is "Argent, a grouse sable regardant crested gules" (Norwegian: I sølv en svart orrhane med hodet vendt bakover).

It is part of the Solør, Vinger og Odal prosti (deanery) in the Diocese of Hamar.

The name Eidskog is ancient and was used for the southern part of Vinger, the region between today's Kongsvinger in Norway and Arvika in Sweden.

The name Eidskog was already in use during the saga period and became, after the canonization of Saint Olaf and important pilgrim's route from Europe to Nidaros Cathedral.

The present Eidskog Church is built on the same site (now called Matrand) and this building was constructed in 1665.

The way through Eidskog was also militarily important and many times through history has been the point of Swedish strikes into Hedmark.

The last Swedish attack through Eidskog was in 1814 when Major General Carl Pontus Gahn on July 31 crossed the border and marched against Kongsvinger.

His forces were stopped at Lier outside Kongsvinger on 2 August 1814 by troops led by Lieutenant Colonel Andreas Samuel Krebs (1769-1818) and retreated to Eidskog.

The municipal council (Kommunestyre) of Eidskog is made up of 25 representatives that are elected to four year terms.