Arenillas, in the judicial district of Almazán, is a small municipality in the province of Soria, with a rich history and a natural environment very characteristic of the Castilian plateau.
The municipality is crossed by the Talegones River (a tributary of the Duero River) and the Parado River.
The landscape is hilly, with grain fields and scrubland.
The economy is based on agriculture (wheat, barley, rye) and sheep farming.
The distillation of aromatic plants such as lavender and spike lavender is particularly noteworthy, giving rise to a small artisanal industry.