Black River Canal Locks North of Boonville

This series of four locks, The Upper Four Combines, is near the point where the Black River Canal began its steep descent toward Carthage after rising equally steeply from Rome along the Lansingkill. 

It sits between the north and south bound lanes of Route 12. Much can be learned about how the locks were operated by studying the remaining hardware.

The Boonville Black RIver Canal Museum site has tons of interesting information:

Boonville Black River Canal Museum