Niederlahnstein is a part of the city of Lahnstein in Rhineland-Palatinate in Germany.
Niederlahnstein obtained civic rights in 1332, and was until 1803 on the territory of the elector of Trier.
Here on 1 January 1814 a part of the Russian army crossed the Rhine.
In the vicinity are the Johanniskirche, of a Romanesque design, and the Allerheiligenberg, whereon stands a chapel, once a famous place of pilgrimage.
On 7 June 1969, Niederlahnstein was joined with Oberlahnstein to form the city of Lahnstein.