Fectio, known as Vechten in Old Dutch, was a Roman castellum in the province Germania Inferior established in the year 4 or 5 AD. It was located at the place where the river Vecht (Fectio) branched off from the Rhine, leading to Lake Flevo, which was later to become the Zuiderzee. This was near the modern hamlet of Vechten in the municipality Bunnik, Utrecht, Netherlands.