Herøy is a municipality in Nordland county, Norway. It is part of the Helgeland traditional region. The administrative centre of the municipality is the village of Silvalen. The municipality is located about 15 kilometres (9.3 mi) west of the town of Sandnessjøen.

Helgeland is the most southerly district in Northern Norway. Generally speaking, Helgeland refers to the part of Nordland county that is located south of the Arctic Circle. It is bordered in the north by the Saltfjellet mountains and Svartisen glacier, which form a natural border with the Salten district. In the south, Helgeland borders Trøndelag county.