Frösthults kyrka

The church's core, including the nave and sacristy, was built around the year 1300. A distinctive group of three windows in the chancel's east gable survives from this period, a feature shared with several churches in Uppland and Västmanland built between 1280 and 1310. The original timber barrel vault was replaced in the late fifteenth century, probably between 1470 and 1490, with the brick star vault still seen today. The vault ribs once carried carved figures, later removed, though two carved faces survive at the crown of the chancel window.

Inside, painted fragments from the seventeenth century remain, including an inscription above the three-window group dated 1637 with decorative scrollwork nearby. No medieval wall paintings have survived. A rood screen separated the chancel from the rest of the church until around the mid-eighteenth century, though its age and appearance are not recorded.

The church's external appearance changed considerably in the nineteenth century. A neoclassical tower was added between 1839 and 1843, replacing a freestanding bell frame built in 1615, and the church bells were moved into the new tower. A new main entrance was cut into the tower's west wall, the medieval porch on the south side was demolished, the old south entrance blocked, windows enlarged, and the exterior walls limewashed. A twentieth-century restoration later sought to recover some of the church's earlier character, uncovering and conserving the seventeenth-century paintings and restoring original colours to the altarpiece and pulpit.

The altar, altarpiece and pulpit were carved in the 1740s by the Uppland woodcarver Magnus Granlund, with scenes including the Last Supper and Christ's agony in Gethsemane. The font, made of Gotland limestone, dates from the mid-thirteenth century. The current organ, built in the 1920s by a German firm, incorporates the façade of an earlier eighteenth-century instrument.

Buried in the chancel beside the altar is Johannes Campanius, the parish's incumbent, who served as a missionary to Indigenous communities in New Sweden, North America, during the 1640s. He is also linked to a brass candelabrum given to the church in 1653 and a bell acquired in 1656.