Osthofen is a town in the middle of the Wonnegau in the Alzey-Worms district in Rhineland-Palatinate, Germany. Since 1 July 2014 it is part of the Verbandsgemeinde (a kind of collective municipality) Wonnegau. Osthofen was raised to town on 24 October 1970.
The town lies in Rhenish Hesse where the river Seebach, a very short river that rises in neighbouring Westhofen and flows for only 9 km, empties into the Rhine.
Archaeological finds have established that the Osthofen municipal area was already settled at least four thousand years ago. The town had its first documentary mention in the Lorsch codex as Ostowa in a document dated to 784. It is believed that Osthofen was founded by people from either the now amalgamated village of Mühlheim or the Merovingian royal palace that once stood in Worms-Neuhausen.
On Osthofen’s Goldberg (mountain), a chapel to Saint Remigius might have been built as early as the 6th century. This is where the first major estate was, which by 1195 had grown into an Imperial castle. In Mühlheim, the Knights Templar likewise built a castle in 1215.