Reichenstein Castle, Medieval castle in Tragwein, Austria.

Reichenstein Castle is the half-ruin of a hilltop castle converted into a Renaissance palace, set on a narrow rock ridge above a bend of the Waldaist in Tragwein, Upper Austria. Of the medieval castle only the chapel survives; in 1576 a residential wing replaced the medieval palas, and its Rittersaal still shows remains of frescoes. A section of the gate building and the northern flanking tower also stand.

A document of 1230 first names Ulrich von Reichenstein; the medieval castle itself is dated to between 1230 and 1300. The Kapeller family held it from 1295 to 1406, followed by the Wallseer and Liechtensteiner. In 1565 the knight Christoph Haym bought it, and from 1567 he rebuilt it as a Renaissance palace; his son Hans continued the work. Since 1729 it has belonged to the Starhemberg family.

The name Reichenstein comes from Middle High German rîch(e) and stein, meaning a mighty castle on rock. The chapel, which holds Christoph Haym's epitaph, served as the parish church from 1785 to 1816 and is still used for weddings and baptisms.

The castle stands on a narrow rock ridge above a bend of the Waldaist, with the village of Reichenstein at its foot. The half-underground museum building opened in 2013, and the chapel with Christoph Haym's epitaph is still used for weddings and baptisms. The site has been under restoration since 1989.

The 2012 construction of the castle museum uncovered substantial remains of an older predecessor castle on the grounds. The museum itself, opened in 2013, is a half-underground new building that also houses a Natura 2000 information point for the Waldaist-Naarn area.