Hållö, Rocky island in Bohuslän, Sweden

Hållö is a granite island in the Bohuslän archipelago, near Smögen and Kungshamn in Sotenäs municipality. Its western side holds Marmorbassängen, a rock basin with turquoise water, and the flat rock slab Slätte hälla, formed by frost weathering and waves. Bohuslän's oldest lighthouse stands on the island, and the former radio direction-finding house south of it now serves as a hostel.

The lighthouse was constructed in 1842 and has served as a key navigation marker for ships along the Swedish coast ever since. The structure stands as evidence of the region's maritime navigation history.

On a flat rock near Hållö harbour, two series of rock carvings show a sun wheel among other motifs; they are estimated to be about 500 years old. South of the lighthouse, the old radio direction-finding station, built in 1922, now houses the Utpost Hållö hostel.

The island is reachable by regular ferry services from Smögen harbor, particularly accessible during warmer months. Sturdy footwear is advisable since the paths cross uneven rocky terrain.

Marmorbassängen, on the island's west side, is a rock basin whose water is noted for its clear turquoise colour. South of it lies Kålhageklåvan, where the lighthouse keepers once grew crops in the thin soil. Nearby Slätte hälla is a broad flat rock slab, and two giant's kettles lie south of it, one over four metres deep.