This unused LINEN postcard is from the era of approximate 1940-1950's and is in excellent unused condition for it's age. 

Picture shows the Trout Hatchery on the building that has the water wheel.  This is part of the Ohio's Lake Erie Vacationland. The back of the card says: THE TROUT HATCHERY AT THE BLUE HOLE, CASTALIA, OHIO.  A visit to the famous Blue Hole is not complete without also visiting the Trout Hatchery located in the same grounds.  The streams around this interesting place are alive with various species of beautiful trout.  Located at Castalia, Ohio, six miles west of Sandusky, on State Route 101 and Federal Route 6, Open day and night.

Please see picture of front & back for more accurate detailing & feel free to ask questions. Actually, the postcard looks nicer then the picture shows. The scan turned out sort of grainy looking. The actual picture doesn't look like this.