Kasteelruïne Ouborg

Swalmen, Netherlands, Netherlands

---

Kasteelruïne Ouborg in Swalmen, Netherlands, was founded in the 14th century by Seger Vosken as a rectangular stronghold measuring about 25 by 17 meters along the Swalm River, featuring thick 1.5-meter walls, an L-shaped residential wing around a courtyard, and a unique elongated octagonal donjon tower that stands as the only visible remnant today.

Sold in 1331 to Reinoud II of Gelre amid financial troubles and later passing through families like Van Swalmen, Van Oost, and Schenk van Nydeggen until around 1380, it lost importance, suffered fire damage in the 15th century, and gradually decayed into ruins with stones quarried for local use like church repairs in 1916.

Archaeological digs in 1962 by Jaap Renaud uncovered foundations, a vaulted cellar, and stair tower remnants, preserving it as one of the Netherlands' oldest castle ruins near the preserved Hillenraad Castle.