Põhja-Kõrvemaa Nature Reserve (Estonian: Põhja-Kõrvemaa looduskaitseala) is a protected area in Harju County, Northern Estonia, some 50 km east of Tallinn. With an area of 130.9 km2, it is the third largest nature reserve in Estonia. Dominated by forests and bogs, it aims to protect rare and endangered species, their habitats, and valuable natural landscapes.