Agö lighthouse, Sector light in Hudiksvall Municipality, Sweden.

Agö lighthouse is a 15-metre circular reinforced-concrete tower with a gallery and lantern, painted white with a red band at mid-height. It stands about 10 metres from the old wooden keeper's house, whose gable once held the original light. Its focal plane is 31 metres above the sea.

A signal station was established at Agö in 1860, with the original light mounted on the roof of a wooden keeper's house. In 1884 a new lighthouse was built against the house's gable; it remained inhabited until 1973. Since 1970 a 15-metre reinforced concrete tower about 10 metres from the old lighthouse has served as the active light, electrified and automated in 1973.

The name Agö fyr comes from the island of Agön in the Botnian Sea, about 30 km southeast of Hudiksvall. The original light was placed on the roof of the lighthouse keeper's wooden house, and the present tower stands against the house gable. The station has been automated since 1973, and the old lighthouse was inhabited until then.

The beacon can be viewed from sea routes or coastal approaches, best visible during twilight hours when the colored signals stand out clearly. Access is easiest from local waterways, making it practical to visit by boat with local guidance.

The beacon uses a system of colored light sectors that automatically warn ships if they drift too far from the safe channel. This design allows boat operators to check their position at night without relying on additional equipment.