Delvenau

{{short description|River in Germany}}{{More citations needed|date=June 2024}}{{Expand German|topic=geo|date=September 2011|Delvenau}}

{{Infobox river

| name = Delvenau

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| mouth_location = Elbe–Lübeck Canal

| mouth_coordinates = {{coord|53|22|26|N|10|34|51|E|region:DE-SH_type:waterbody_source:kolossus-dewiki|display=it}}

| progression = Elbe–Lübeck Canal→ {{RElbe}}

| subdivision_type1 = Country

| subdivision_name1 = Germany

| subdivision_type2 = States

| subdivision_name2 = Schleswig-Holstein and Mecklenburg-Vorpommern

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Delvenau (incorrectly known today as: Stecknitz) is a {{convert|50|km|mi|adj=mid|-long}} river in Herzogtum Lauenburg in Schleswig-Holstein, Germany.{{Cite book |last=Greule |first=Albrecht |title=Deutsches Gewässernamenbuch: Etymologie der Gewässernamen und der zugehörigen Gebiets-, Siedlungs- und Flurnamen |date=2014 |publisher=De Gruyter |location=Berlin; Boston |language=de |doi=10.1515/9783110338591|isbn=978-3-11-019039-7 }}{{Additional source needed|date=June 2024}} It begins in Büchen, flows to the Elbe–Lübeck Canal near its confluence with the Elbe in Lauenburg. The lower section between Bröthen and Lauenburg forms the border between Schleswig-Holstein and Mecklenburg-Vorpommern.

The name Delvenau originates from the Middle Low German word delf meaning trench.