Rossgarten (German: Roßgarten) was a quarter of northeastern Königsberg, Germany. It was also occasionally known as Altrossgarten (Altroßgarten) to differentiate it from Neurossgarten in northwestern Königsberg. Its territory is now part of the Leningradsky District of Kaliningrad, Russia.
Rossgarten was first mentioned as the Roß- und Rindergarten (horse and cattle pasture) in the 1300 town charter of Löbenicht. It grew to encompass the eastern shore of the Schlossteich and reached the southern shore of the Oberteich. Neighboring districts were Burgfreiheit to the southwest, Neue Sorge to the south, the Herzogsacker fields to the east, and the 17th century Königsberg fortifications to the north. Located outside of the walls was Kalthof to the east and the Pferderennbahn, or horse racing track, in Carolinenhof to the northeast.
According to observations by Caspar Hennenberger, in 1539 the territory was still undeveloped, with an inn and warehouses the only buildings of note. In 1540 Albert I, Duke of Prussia, approved development of a new suburb known first as Neue Huben and then as Roßgarten. It was declared a Freiheit subordinate to Königsberg Castle in 1542. East Prussian noble families who lived in Rossgarten included the Buddenbrock, Gröben, Götzen, Kunheim, Ostau, Rauter, Schlieben, and Tettau. Many Dutch linen weavers settled in the new suburb by 1553.Latvian merchants also settled in Rossgarten.