Pormaļu Silvermound is a Selonian Hillfort on the left bank of the Daugava. It blends perfectly into the surrounding landscape and is considered one of the Iron Age hillforts. Silvermound is single, in the shape of a rounded cone and with very steep edges. The mound rises 22-26 meters above the surrounding area. The size of the hillfort site is 45- 50 meters, in the middle part of the site there is a small rampart of about three meters, and it does not have any visible man-made fortifications. Stone axes, iron spears, and an iron narrow-bladed ax were found near the hillfort. Next to the hillfort was an ancient city with an area of about two hectares, and the thickness of the cultural layer in it reached 0.6 meters. Ceramics found in the territory of the mound and the ancient city testify that the hillfort has been inhabited for a long time, probably since the 1st millennium BC to the Late Iron Age. The hillfort was first recorded by Karl von Liouvis of Menar (German Karl von Löwis of Menar) in 1922, and in 1926 it was investigated and measured by Ernests Brastiņš during his exploration expedition of the Semigallia hillforts. Near the hillfort there are several isolated round mounds, possibly cult sites.