Styresholm, Medieval fortress ruins in Kramfors, Sweden.

Styresholm is a fortress ruin on the banks of the Ångermanälven river in Kramfors, dating from a period when water levels were significantly higher. The remains show stone structures and earthen mounds that mark where this defensive stronghold once stood.

Styresholm was built in the late 14th century by the Victual Brothers as one of a chain of fortresses along the Gulf of Bothnia. Its name is first recorded in 1398, when ownership passed to Queen Margaret I; by 1400 a Danish governor was collecting taxes on trade there. The site lies at Prästmon in Torsåker parish, Kramfors Municipality.

The name Styresholm comes from Styrån, the medieval name of this stretch of the Ångermanälven. The fort was a fogdeborg, a bailiff's castle where Danish governors collected taxes on trade after Queen Margaret took it over. About 250 metres northwest lie the remains of Pukeborg, named after the rebel Erik Puke.

Styresholm lies by the Ångermanälven at Prästmon in Torsåker parish, about 250 metres southeast of the remains called Pukeborg. The surviving earthworks are plateaus separated by deep moats, reachable on foot; the river is still navigable by boat from the sea.

About 250 metres north-west of Styresholm lie the remains of another medieval fortification, later called Pukeborg after Erik Puke, one of the leaders of the Engelbrekt rebellion. Both sites survive as flat plateaus separated by deep moats.