Eslida is a municipality in the province of Castellón, within the Valencian Community of eastern Spain. It is one of the inland towns of the region, situated in the comarca of the Plana Baixa, in the Sierra de Espadán area.
The town lies in a mountainous setting surrounded by cork oak and pine woodland, terrain characteristic of the Sierra de Espadán natural park. Its historic core retains narrow, winding streets typical of Valencian mountain villages, and the local economy has traditionally been tied to agriculture, particularly the cultivation of olives and carob, along with cork harvesting from the surrounding forests.
Eslida is located roughly 20 kilometres inland from the Mediterranean coast, near the towns of Artana and Aín. It is accessible by road from the coastal city of Castellón de la Plana and from the nearby town of Onda.