Torönsborg, Manor house in Söderköping Municipality, Sweden

Torönsborg is a stone manor house of two storeys with a three-storey central section, measuring 39 metres by 15 metres with 13 and five window bays. It was built 1736–56 to plans by Carl Hårleman and stands on a high promontory in Dragsviken on Torön. Two single-storey wings of eight rooms each were added in 1750 and 1761.

Torönsborg was originally called Drags säteri, a name recalling that boats were hauled across the nearby isthmus. In the Middle Ages it belonged to Duke Bengt Algotsson, Bo Jonsson (Grip) and King Karl Knutsson; Karl's daughter Christina married Erik Eriksson Gyllenstierna, whose family held it for over 300 years. It became a säteri in 1645, was burned by the Russians in 1719, and the stone main building was erected 1736–56 to plans by Carl Hårleman. In 1809 it passed by inheritance to Count Carl Gustaf Mörner af Morlanda.

The name Torönsborg replaced Drags säteri, which came from dragging boats across the narrow isthmus now called Näset on Dragsviken's western shore. The estate stayed with the Gyllenstierna family for over 300 years after Christina Karlsdotter Bonde married Erik Eriksson Gyllenstierna. Since 1809 it has belonged to the Mörner family.

The estate lies in Sankt Anna parish on the Torön mainland, 33 km southeast of Söderköping, on a high promontory in Dragsviken. The old country road between Söderköping and Norra Finnö once ran between the main building and the two grain magazines. The main building was designated a listed building (byggnadsminne) in 1976.

The estate library, bought from Stegeborg Castle in the early 20th century by Countess Ebba Mörner, holds 8,500 volumes, mostly 18th-century French literature. Its oldest book, printed in 1557, is a Latin treatise on Euclid's geometry. The collection was assembled at Stegeborg by Philip Werner von Schwerin.