I know where to look for lock 91!

I am excited!   I know where to look for lock 91 and I know why I couldn’t find the water feature described by the Museum Center volunteer that day.   I was looking in the wrong place.   In case you have no idea what I’m talking about, check out In Search of Lock 91 and then come back.   This will make more sense.

One of the things I learned in researching the Miami Erie canal in this area after I found lock 38 in West Chester (you can also read about that adventure) is that the next lock south from lock 38 is supposed to be lock 39.  Oddly though, the plat maps show the next lock south from 38 as lock 91.  The discrepancy didn’t make any sense, and it wasn’t until I started researching lock numbering that I figured out at least part of the equation.

Locks on the Miami Erie canal are numbered sequentially starting, believe it or not, in the middle of the state at the highest point in the canal elevation.  From there, they are numbered sequentially higher as they move away from the highest point, so you’ll find that the lock 38 I’ve reported on is the SOUTH lock 38.  The NORTH lock 38 is in Defiance and was apparently covered over when they built city buildings.

What is interesting though is that the lock numbers in this scheme generally do not match the lock numbers indicated on the plat maps.  It’s not clear to me how the plat maps were numbered, but I speculate that it may be related to the order that the locks were built.  Considering there were 103 locks on the canal, it’s certainly plausible that the Cresentville lock could be 91 as the plat map indicates.  I suspect the more widely accepted “current” designations came later.

Regardless what number you wish to use, there is (was) clearly a lock in the vicinity of the Butler/Hamilton county line near Crescentville, and I suspect the wood that the volunteer showed me is the remains of the lock floor.  Setting out to try to determine an exact location, I was finally able to understand the scaling on the plat maps and then use that the relate them to current map features.

The plat maps are scaled in 1″=100 feet.   Using that and reviewing the beginning and ending maps, I was able to understand that the increasing marker number that runs along the length of the canal actually marks 100 ft intervals from the start of the canal at the north end.  It functions much like a mile marker, albeit with much higher resolution.   For example, lock 91 (South 39) is located at marker 11928 indicating that it’s 11928*100 ft or 1192800 ft from the start of the canal at the north end.  Translated into miles that’s 1192800 / 5280 =  225.9 miles from the start of the canal.  Given that the canal was 249 miles long (not counting branches), that puts lock 91 (South 39) about 23.1 miles from the end of the line at the Ohio River.

Learning all of that made it much easier to scale the old plat maps to currently available topo maps and in fact, I did some graphics work to overlay the old maps onto new ones.

Once I did that, I can see that I was looking in the wrong area.   The remains of the lock would be 100-150 south of Crescentville at the most.  I had been looking much further south than that.  As you might imagine, I can’t wait to get over there for another look around!

I was also able to determine the approximate location for the Crescentville Aqueduct as well.  According to a historical survey, allegedly the abutments still exist.  I’ll be looking for those as well.

Watch for pictures and more details soon!