Astravas is a part of the town of Biržai on the northern shore of Lake Širvėna, by the Apaščia River. In 1811 Prince Dominik Radziwiłł sold the Biržai estates to Count Michał Tyszkiewicz, but only in 1844, after long legal disputes, was the purchase legally confirmed for the Tyszkiewicz family. They did not rebuild the ruined fortress, but established their residence on the other side of Lake Širvėna. In 1862 the counts built a two-storey palace with a belvedere tower at Astravas. Built in the style of an Italian villa, the palace is one of the most beautiful manor residences of the Romantic period in Lithuania. It held part of the Tyszkiewicz and Radziwiłł archives and a library with books from the 15th–17th centuries; its archaeological, ethnographic and art collections were taken to Vilnius and Paris in the late 19th and early 20th centuries. Besides the palace, the manor complex included stables, a huntsman's house, a mill, farm buildings and a dam-bridge. The palace was surrounded by a cosy park with ponds. The bridge-dam built in 1860 held back the waters of Lake Širvėna until 1986. At the entrance stood two cast-metal lions brought from St Petersburg, which in 1938 were given as a gift to the garden of the Vytautas the Great War Museum in Kaunas. Today the Astravas palace is adorned with cement copies of the lions. In 1924 a dairy was set up at Astravas Manor, later a factory making tow sacks and twine, and in 1928 the "Siūlas" linen fabric factory, which still operates today. In 1956–1965 the palace was restored and part of the park was tidied up, and in 1987 the footbridge across the lake linking the manor estate with the town of Biržai was rebuilt. Only the manor grounds and park are open to visitors, as the palace houses the administration of the "Siūlas" linen fabric factory.