Schloss Breill, Medieval castle in Geilenkirchen, Germany.

Schloss Breill is a medieval castle near Geilenkirchen built from red brick with two square towers at its western corners. The structure features a mansard roof and is surrounded by a four-winged economic courtyard adjacent to its main courtyard.

The property began as a medieval motte in the 12th century. It underwent several modifications from the 17th to the 19th century but suffered severe damage during World War II.

The name Breill first appears in 1118; a family styled von Breill is recorded from 1287, also written Breiloo, Breiloe and Breloe. The estate passed by marriage in 1512, when Adelheid von Breiloe wed Reinhard von Goltstein, and stayed with his descendants, raised to comital rank in 1694, into the 19th century. The gate at the end of the 350-metre Breiller Allee carries the alliance of Goltstein and Quadt with the year 1754.

The castle sits south of Bundesstrasse 221 between Geilenkirchen and Übach-Palenberg in an easily accessible location by road. Since the site is not open to the public, visitors can view it only from outside.

The 1728 rebuild added a large economic courtyard east of the old castle, and around 1754 Johann Joseph Couven redesigned the manor house, removing the double moat and laying out a park. The surviving south wing keeps a blue-stone doorway with the Goltstein–von Quadt alliance coat of arms and the year 1754.