The fortress Chertigrad is located 3 kilometers south-east of village of Brusen and 3 kilometers north-east from the village of Yamna (Etropole municipality), which appears to be the most convenient starting point to the fortress. Because the terrain is really difficult, the fortress can be reached for about an hour and a half, following the marked path called "The path of Benkovski". Other villages located nearby are Lopyan and Cherni Vit.
Originally it was a Thracian fortress built in the period IV-III century BC. and judging from the artifacts most likely was acting to VI century. Ancient builders have shown remarkable skill in the use of terrain features such as staked on the base of the wall rock. The fortress is located at 1284 meters altitude, surrounded by steep cliffs, up to 100m high, making it difficult to conquest and easy for defence. It is located on a typical "growth" of the watershed ridge, separating the valleys of the Old River and Cherni Vit River. The fortress is separated from the ridge by a narrow isthmus, on which the wall was built, and its remains are 2.50 meters high. The only accessible point was the south side and there was built the only solid wall of medium sized stones without mortar.
According the archaeologists the name of the fortress comes from Old-Bulgarian and means "a fortress, that only the devils can conquer".
In the eastern part of Chertigrad, a sanctuary can be seen, which was dedicated to the cult of the Sun - a ground with a small niche in the rock, where the first rays of the sun are falling. At the very top there was a spring which today is dry.