Kleinkastell Oberranna, Roman fortification in Engelhartszell an der Donau, Austria

Kleinkastell Oberranna is a late antique Roman burgus on the right bank of the Danube in Oberranna, a district of Engelhartszell. Excavations in 1840–1842 uncovered the south-east wall with two round corner towers; the surviving masonry of the south-west outer wall stands about 1.6 m high. The completely preserved lower storey of the north tower was incorporated into the foundation of a building erected around 1500.

The fort was discovered in 1840, when the Schlögen excavation society uncovered its southeast wall with two round corner towers. It was built in late antiquity as part of the Danube Limes in Noricum, probably under Valentinian I, and was destroyed by fire in the early 5th century. Around 1500 the site was resettled, and the intact lower storey of the north tower was incorporated into a new building.

The identification with the Stanacum of the Itinerarium Antonini rests on distances: 20 Roman miles from Boiodurum (Passau) and 18 from Iovacum (Schlögen), which match Oberranna. The name appears in no other late-antique source, and the site is not listed in the Notitia Dignitatum or the Tabula Peutingeriana.

The remains lie on the right bank of the Danube beside the B130, about 11 km upstream of Schlögen where the valley widens; the road was shifted west in 2017 so the excavation could proceed. The exposed walls stand roughly 1.6 m high, and the site is a protected monument.

The identification with Stanacum rests on distances in the Itinerarium Antonini: 20 Roman miles from Boiodurum (Passau) and 18 from Iovacum (Schlögen), which match Oberranna exactly. The site is absent from the Notitia Dignitatum and the Tabula Peutingeriana. The name is probable, not certain.