Seeberg Castle situated on a high rocky spur above a brook (its Czech name literally means "Spur") was probably founded in the 1200’s as the manor house of ministeriales subject to the imperial palatinate in Cheb. Ostroh had already been inhabited in prehistoric times as evidenced by a fortified settlement surrounded by a wall and two cross moats, which were probably used during the building of the later Romanesque castle. Nonetheless, the castle was first referred to in written records only in 1322 when it was denoted as part of the pledge of Egerland (German name for the district of Cheb) to King Jan of Luxembourg (also denoted as John of Bohemia).
The estate had been under the administration and in possession of the town of Cheb before Emperor Sigmund of the House of Luxemburg gave it to his Chancellor, Kašpar Šlik, originally a patrician of Cheb, in 1434. When Cheb Councillor Kaspar Juncker purchased Seeberg Castle in 1461, it had already become desolate. Following the death of Juncker's heirs, the castle was acquired by brothers Konrad and Jost of Neuberg in 1497. Konrad fought a long-lasting local war with his neighbour, Jorg of Zedwitz, the owner of the nearby Liebenstein Castle (present-day Libá), who despoiled a large part of the Seeberg estate.
During the Thirty Years War, Seeberg was taken by the Swedish army of General Königsmark in 1648, plundered and set on fire. In consequence, the castle had to be repaired by its owner, Vitus Dietrich of Steinheim, after the Swedes had left. With the decease of the last male heir, the castle was assigned as escheat to the Royal Chamber of Bohemia and Emperor Leopold I conveyed it to his Chamber Counsel, Chamberlain and Supreme Chancellor, Baronet Johann Hartwig of Nostitz. In 1703, Seeberg Castle passed into the possession of the town of Cheb.
The castle was designed into two sections. The outer ward was separated from the inner ward and bailey by a moat with an access bridge. The Romanesque castle was encircled by a wall, which we may still find today on the front side of the castle along with the existing inner gate that had been adjoined by a tower structure at the northeast corner. In the course of further construction and enlargement of the Gothic castle, a new gate and gateway were built outside the castle front, as well as a palace along the southern wall. A barbican was established along the eastern and southern outer walls and a third moat with a drawbridge intersected the rear part of the rocky spur.
The structures built in this westernmost part of the rocky spur were probably torn down during the Renaissance reconstruction of the castle that took place in the 16th century when the castle belonged to the Neuberg family. The terrain of the rear rocky spur was levelled and the third moat was filled up. Moreover, a new wing connecting the tower structure in the north with the south palace was built in the eastern part of the barbican. The side of the wing facing the courtyard was decorated with Renaissance arcades.
After being raided by the Swedish army, the castle was subject only to minor repairs and the castle buildings were later raised by one floor. The old drawbridge was removed and replaced by new masonry pillars between 1724 and 1726. The town of Cheb utilised the castle primarily for husbandry purposes. In the 1800s, the tower above the outer ward gate was pulled down and the outer moat was filled up. Renovation works taking place between 1905 and 1915 saved the castle from collapsing. Nonetheless, the condition of all the castle premises was neglected once again after World War II.
An overall renovation of the castle complex launched by the Františkovy Lázně Town Museum in the mid 1970’s was successfully completed in 1990 with the grand opening of Ostroh Castle. The castle palace houses a display dedicated to the development of styles of its 19th century interiors, ranging from Empire style up to Chippendale of the first quarter of the 20th century. An open-hearth kitchen and a knight's hall (ceremonial hall) may be found in the oldest part of the castle. An open-air folk architecture exhibition with a display mapping the life of country folk of northwest Bohemia is installed in the outer ward.