Stjernsund Castle, Manor house in Askersund Municipality, Sweden

Stjernsund Castle is a two-storey manor house with a lower service floor, built 1798–1801 to designs by Carl Fredrik Sundvall in the Neoclassical style. Its cream-coloured facade has a projecting central portico carried by four columns on a broad stone stair, with the date MDCCXCVI in a panel above the entrance. It stands on a high headland between Stora Hammarsundet and Lake Alsen.

The estate was formed in 1637 when Johan Gabrielsson Oxenstierna merged the farms Ölmesund, Åviken and Stockbråtet. In 1785 it was sold to ironworks owner Olof Burén, ennobled Burenstam, who had the present castle built between 1798 and 1801 to designs by Carl Fredrik Sundvall. King Karl XIV Johan bought it in 1823, and Oscar I sold it in 1851 to his son Prince Gustaf.

Prince Gustaf, known as a talented singer, lived here in the 1850s and filled the rooms with fine furnishings and artworks that reflected royal taste. These decorated interiors remain on display today and give visitors a sense of how the nobility lived during that era.

The castle opens to the public in summer; the grounds sit on a high headland between Stora Hammarsundet and Alsen, at the northern end of Lake Vättern. On site are a carriage museum, a dairy and a café. The raised entrance is reached by a broad stone stair.

The estate is the parent farm of the Svensk rödbrokig boskap, the Swedish Red-and-White cattle breed, according to the sources. The breed name is often shortened to SRB in Swedish agricultural use.