It is believed that Sprūdė Hillfort was the domain of Duke Sprūdeikis, brother of Mindaugas, King of Lithuania. Sprūdeikis angered his brother and fled to Samogitia, where he built his castle in the safest and most easily defended location – Sprūdė Hill. However, even this did not protect him. His brother's wrath found him here too. Sprūdeikis knew where to settle. The hillfort offers excellent views of the Varniai basin, where the large lakes Biržulis and Lūkstas lie, and the hillforts of Varniai, Luokė, Šatrijos, Girgždūtės, and Medvėgalis are clearly visible. The hillfort is attributed to the "parako gadyne" period – the later period of battles with the Teutonic Knights. Its platform is 216 m above sea level and is round. The hillfort is surrounded by three ramparts, which are up to 4 m high. Stone axes and spearheads have been found in the vicinity of the hillfort.