Obama Castle (Obama-jō) is a castle located in Obama, Fukui Prefecture, Japan. The castle is also known as Unpin Castle (Unpin-jō). In 1601 (Keichō 6), after receiving Wakasa Province due to successes in the Battle of Sekigahara, Kyōgoku Takatsugu built Obama Castle by using local fisherman as workers. In 1634 (Kan'ei 11), Sakai Tadakatsu took control of the castle after the Kyōgoku family moved to Izumo near Matsue. He finally completed the castle tower with 113,000 stones in 1636 (Kan'ei 13), with the tower reaching a height of 29m.
Obama Castle was held by the Sakai family up to the Meiji Restoration in 1868. It was destroyed in a fire in 1871 (Meiji 4) after acting as the prefectural office since the Meiji Restoration, and only the stone walls remain today. The ruins are often referred to as Obama Castle Ruins (Obama-jō Ato) in tourist brochures. The castle grounds now has Obama Jinja (Obama Shrine), a Shinto shrine.