The Castle of Serrella stands at an altitude of 1.050 metres above sea level, on a rocky position with difficult access. Its location, named Penya del Castellet, is in the municipality of Castell de Castells in the region of La Marina Alta, controlling the meeting point of the two valleys of Castells and Guadalest.

The castle is difficult to access. To reach its ruins, one has to exit Castell de Castells by taking the CV-752 highway in the direction of El Castellet and take a signposted path (with white and yellow-coloured signs) to the right, towards El Castellet and Penya Castellet. After walking past a house on the right, branch off to the right along the path following the white and yellow-coloured signs and then a narrower trail to the left, which shortly becomes a route that turns to the left and starts following the ravine known as Barranc de Gaspar. The route goes up to a dirt road with signs. Turn to the left towards Penya Castellet and it is possible to see the ruins of the castle at the top of the rock, on the right-hand side.

Both the castle as well as the town are of muslim origin. It is one of the most cited castles in the Pact of Pouet signed in the Castle of Alcalà.

In 1254, it was conquered by Jaume I. In 1290, Bernat of Sarriá was given possession of it, and later it passed into the hands of the Order of Calatrava.

The decree of expulsion provoked uprisings and riots in the area, until they were suppressed in the battle of Pla de Petracos.

It was repopulated by Christians from Majorca. The castle was probably abandoned at an early date, after the conquest.

The fortification is composed of two precincts, one in the summit and another in the rocky location. The remains that have reached modern times are scarce; among them are some half-destroyed parts of the walls, a cistern, and the lower parts of some towers; the biggest of them, at the peak of the mountain, stands out.