| Niederelbe | |
| Subdivision Type1: | Country |
| Subdivision Name1: | Germany |
| Subdivision Type2: | State |
| Subdivision Name2: | Hamburg–Cuxhaven |
| Length: | 108abbr=onNaNabbr=on |
| Width Min: | 2abbr=onNaNabbr=on |
| Width Max: | 18abbr=onNaNabbr=on |
| Depth Max: | 30abbr=onNaNabbr=on |
| River System: | Elbe |
The Niederelbe (i.e. Lower Elbe) is a 108abbr=offNaNabbr=off long section of the river Elbe, from western Hamburg downstream to its mouth into the North Sea near Cuxhaven. Starting at (or Elbe kilometer 634) near Finkenwerder, Hamburg, it gradually widens from 2abbr=onNaNabbr=on to 18abbr=onNaNabbr=on. Once passing the Hamburg state border, the Niederelbe also forms the border between the states of Lower Saxony and Schleswig-Holstein.
The Niederelbe forms part of the Elbe section named the Unterelbe (i. e. Lower ("Under") Elbe), comprising all parts of the Elbe influenced by the North Sea's tides, starting further inland at the sluice in Geesthacht (or Elbe kilometer 586).