Conversation so far:
where does the allegheny river start and end
The Allegheny rises in north central Pennsylvania, in central Potter County and joins with the Monongahela River at The Point in Downtown Pittsburgh, Pennsylvania to form the Ohio River
how long is the allegheny river
The Allegheny river is approximately 325 miles long

Question: where does the name come from
Self-contained rewrite: where does the name allegheny river come from