- Allegheny, Allegheny River - a river that rises in Pennsylvania and flows north into New York and then back south through Pennsylvania again to join the Monongahela River at Pittsburgh which is the beginning of the Ohio River
--1 is a kind of range, mountain range, range of mountains, chain, mountain chain, chain of mountains; river; range, mountain range, range of mountains, chain, mountain chain, chain of mountains; river
--1 is a part of