Lielkalnu hill fort is located 3 km west of Irši and 2.5 km south of Liepkalne church, next to the former Lielkalni and Nomaļi farmsteads. During WWII, Lielkalnu hill fort was heavily damaged with various trenches, but at the beginning of 1990s it was almost entirely destroyed after a sand pit was dug. Lielkalni hill fort was still used in the 10th century.