The town’s history is shaped by its favourable location at the confluence of the rivers Lahn and Rhine. As far back as the early Middle Ages, the formerly autonomous town of Oberlahnstein with its boat landing stage is already an important centre of trade. Here goods are transferred between Lahn skiffs and Rhine barges and merchants sell their wares. The local rulers, the Archbishops and Electors of Mainz, also appreciate the advantage of the site at the mouth of the river. In 1298 they install a toll station here at the northwestern border of their territory. This is protected by its own fortification, Martinsburg castle. For many centuries the Oberlahnstein toll provides a lucrative source of income which also benefits the town.
To facilitate the mooring and loading of the numerous boats, the Rhine river bank is frequently remodelled. The rapid rise of steam navigation in the mid 19th century requires the construction of an efficient river port. Work on a first, small harbour begins in the year 1860. The new Lahn Valley Railway link provides access to the Lahn marble quarries as well as the iron-ore, limestone and basalt-stone reserves of the Westerwald and Taunus. The port quickly becomes an important transshipment point between land and water.
As a result of Oberlahnstein’s subsequent development into an industrial centre, the port is extended several times and its goods yard is also considerably enlarged. In 1939 the harbour entrance, which was originally from the Rhine, is replaced by the present access from the Lahn.
The harbour offers the boats shelter during periods of ice-drift. In some winters over 100 vessels are moored here. The harbour only loses this important function in the 1960s when the the increasing pollution and warming of the Rhine prevents the river from freezing over.
The Rhine river bank has also evolved over the years. In 1862 Oberlahnstein’s Historic riverside backdrop falls victim to the harbour’s new railway link. Only a few years later in 1885 the river bank is considerably broadened as part of the relocation of the mouth of the river Lahn. The new harbour head peninsula is built, with access via the harbour embankment. An attractive Rhineside promenade is created between Martinsburg Castle and the port. This quickly becomes a popular tourist magnet. Many visitors from near and far still arrive at Lahnstein by boat on their journey through the UNESCO Upper Middle Rhine Valley World Heritage site. From here on the banks of the Rhine they get their first glimpse of the town at the mouth of the Lahn.