Sloup is a medieval castle in Czech.

Sloup is a medieval castle in Czech. It is near Nový Bor in the small town of Sloup v Čechách, in the Liberec Region, north Bohemia, Czech Republic. It takes its name from the special appearance of the freestanding sandstone rocks, 33-metre (108 ft) high, into which it was carved in the 14th century. Sloup means "column".

The castle was first mentioned in records dating from 1324. The edges of the outcrop, which was a level summit, were carved to resemble castle walls with loopholes, and some of the gullies in the outcrop were filled in with masonry. Thanks to an ingenious system of trenches it was possible to flood the area around the rocks. The combination of natural conditions and human ingenuity turned the castle into a fortress unassailable by medieval warriors. In 1639 the Swedes burned it down, and the castle became a ruin.

From 1670 to 1785 hermits were based here, making use of the rock for their needs. Among other things, they carved out new rooms and created recesses for the Stations of the Cross, built a chapel in the rock and formed a new entrance.