El Bulín de Horcajuelo is made up of a set of 6 houses located in the upper part of the village, in a very peaceful area and offering superb views of the whole mountain range.
The municipality of Horcajuelo de la Sierra, previously called El Orajuelo, is situated to the north of Madrid, in the southern foothills of the Ayllón massif, which is part of Somosierra. Its total surface area is 24.4 square kilometres and average height is 1,145 m., reaching 2030 m in its extreme northern part and going down to 1050 m in the extreme southern part.
This is a predominantly hard rock area, rugged and rocky scenery, an abundance of small streams that facilitate areas of crops and intensive grazing land.
On the granite peaks, we find scrubland. On the moors, there is an extensive area of pine tree forests and some rockrose. Closer to the village, there are several abandoned pieces of land which were once cultivated. You can also find Pyrenean oak trees, grazing land with holm oak bushes and several crops on pieces of flat land.
The village is set on the edge of a hill, with quite steep slopes home to the streams of Garita and Grande. This is where we get the name "Horcajuelo": horca or village between two rivers.