Altuna Runestone, Viking runestone at Altuna Church, Sweden

The Altuna Runestone is a granite stone 1.95 metres high, now standing near Altuna Church in Enköping. One face shows Thor fishing for the Midgard serpent, his foot pushed through the boat's hull; the runic inscription in Urnes style is signed by the runemasters Frösten and Balle.

The Altuna Runestone was carved in the 11th century in runestone style Pr3, the Urnes style, and is signed by the runemasters Frösten and Balle, with Livsten possibly involved. Balle worked in south-western Uppland and northern Södermanland in the second half of the 11th century. Local historian K. A. Karlinder found the stone in 1918 in the wall of a chapel near its present site, since runestones were often reused as building material.

The stone displays scenes from Norse mythology, particularly Thor fishing for the Midgard Serpent using an ox head as bait. These images connected the local people to their spiritual beliefs and made their ancient gods part of their daily surroundings.

The stone stands in Altuna, in Enköping Municipality, near its find spot: it was taken in 1918 from the wall of a chapel close to where it now stands. It is an outdoor monument in the Fornminnesregistret, visible from the surrounding ground without barriers.

The stone is signed by the runemasters Frösten and Balle, and perhaps by Livsten; Balle worked in south-western Uppland and northern Södermanland in the second half of the 11th century. The inscription is carved in runestone style Pr3, the Urnes style, with slim, stylized animals interwoven in tight patterns.