Engelberger Aa (or ''Engelbergeraa'') is a
river
A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of w ...
in
Switzerland. It rises west of
Surenenpass in the
Canton of Uri, flows through the valley of
Engelberg
Engelberg (lit.: ''mountain of angel(s)'') is a village resort and a municipality in the canton of Obwalden in Switzerland. Besides the village of Engelberg, the municipality also includes the settlements of Grafenort, Oberberg and Schwand.
The ...
(
Obwalden) and
Nidwalden. At
Buochs, it empties into
Lake Lucerne
__NOTOC__
Lake Lucerne (german: Vierwaldstättersee, literally "Lake of the four forested settlements" (in English usually translated as ''forest cantons''), french: lac des Quatre-Cantons, it, lago dei Quattro Cantoni) is a lake in central S ...
and is thus a
tributary
A tributary, or affluent, is a stream or river that flows into a larger stream or main stem (or parent) river or a lake. A tributary does not flow directly into a sea or ocean. Tributaries and the main stem river drain the surrounding drai ...
of the
Reuss, which drains that lake.
Rivers of Switzerland
Rivers of Nidwalden
Rivers of Obwalden
{{Switzerland-river-stub