Castle Netřeb, Gothic castle ruin in Kanice, Czech Republic.

Castle Netřeb is a castle ruin perched on elevated ground in Kanice, with remaining walls, towers, and sections of the original keep visible across the site. The scattered structures reveal the medieval construction methods and defensive layout of this fortress.

Děpolt of Rýzmberk founded the castle around 1325. In 1382 Racek of Švamberk exchanged it with Ješek of Pnětluk, and around 1395 it passed to the Kaničtí z Čachrova. In the 15th century they moved to the Kanice fortress, and a 1528 land register entry records Netřeb as deserted.

The castle's name Netřeb, also recorded as Netřeby, comes from the Kaničtí z Čachrova family, who held it from about 1395 and later moved to a fortress in Kanice. The ruin stands in a nature reserve created to protect yew trees 600–800 years old.

The ruins are accessible year-round and can be explored at your own pace, though the ground is uneven and can be slippery in places. Sturdy footwear and care when walking on older structures are advisable.

The keep's walls taper at each floor through setbacks that supported the timber floors, and the first storey was lit by two slit windows in the west wall, 1.7 m wide inside and narrowing to about 40 cm outside.