The origins of the market town is unknown, due to a lack of documents. It is thought that the first settlers were subjected to a tax from a local Prince, and that it refers to the interest rate payable. These farms were handed down through the generations, locally referred to locally as yards, with locals later referred to as the Lords of Irdning.
The name Irdning (Idenich, Ydnich) is first mentioned in 1140, and the parish church was then mentioned as such in 1145. The market started in 1564 at the request of the ruler Selva Ferdinand Hoffman. Since 1689 it has been the seat of the provincial court Selva Irdning.
On 1 January 1960 the municipality of Irdning was united at the decree of Governor Josef Krainer. The municipality has been twinned with Ahorn, Bavaria in Germany since 1975
