The mound (Pilalė) is located on a separate hill on the left bank of the Virvyčia. The site is square, elongated in the east-west direction, 60 and 35 m in size. Slopes of medium steepness, up to 12 m high.
At the southern and western foothills is a 6-hectare foothill settlement. In the vicinity of the mound, more precisely - in the non-localized area of Užstelgis, there is a burning cemetery at the beginning of the 2nd millennium.
Exploratory archeological research of the mound in 1964. performed by the Lithuanian Institute of History.
The mound dates back to the 1st millennium - the 13th century. It is believed that the mound stood in 1253. April 5 The letter of the Livonian Order and the Curonian Bishop Heinrich on the division of the southern Curonian lands mentions the Curonian castle Ząsūgala.