Berzosilla is a municipality in the province of Palencia, within the autonomous community of Castile and León, Spain. It is located in the north of the country, in the region bordering Cantabria.
The municipality is notable for being an exclave of the province of Palencia: it is separated from the rest of the province and is entirely surrounded by the territory of Cantabria. This makes it one of the small number of Spanish municipalities that are detached from their home province.
According to the 2025 census (INE), Berzosilla has a population of 45 inhabitants, making it one of the least populated municipalities in the province.