Clemensbrunnen in Koblenz, Monumental fountain in Deinhardplatz, Koblenz, Germany.

Clemensbrunnen is a monumental sandstone structure in Koblenz standing nine meters tall with four semicircular basins surrounding a square obelisk. Latin inscriptions cover the obelisk's sides, documenting the fountain's purpose and its original patron.

The first Koblenz aqueduct, completed in 1786, supplied the newly built Electoral Palace with spring water from Metternich. Its builder, Prince Clemens Wenceslaus of Saxony, then had the first public fountain erected on Clemensplatz in 1791, inaugurated on his name day, 23 November. In 1970 it was moved about 75 metres west to Deinhardplatz, in front of the theatre, and its four basins and electoral coat of arms were reconstructed.

The fountain takes its name from its builder, Clemens Wenzeslaus of Saxony, the last Elector of Trier, and was inaugurated on his name day, 23 November 1791. His coat of arms faces the theatre on the pedestal, and the Latin inscription "Clemens Wenceslaus Elector Vicinis suis 1791" addresses it to his neighbours.

The fountain sits on Deinhardplatz directly in front of Koblenz Theater and is easily accessible on foot from the old town. It remains open year-round and serves as a helpful landmark in the city center.

The Latin inscription on the obelisk includes the year 1791 and names the patron explicitly. This detailed historical record in a foreign language preserves the memory of a nearly forgotten regional ruler.