This is an addition to History of Markle's Mill.

According to a May 3, 1931 article in the Terre Haute Tribune-Star written by A. R. Markle (a descendant), Abraham Markle built and operated a mill on Cascadilla Creek in Ithaca, NY in the early 1800s. Markle's home in Ithaca was once the oldest home in the city. It was located near Cascadilla Creek. 

Markle Home in Ithaca, NY 
Markle House at 114 Linn Street in Ithaca, NY ca 1957 (since demolished)

The historical marker in the photo above still exists, but the home does not.

Historical Marker
Historical Marker (Andrews photo)

Eisha Neely, a Research Services Librarian in the Division of Rare Manuscript Collections at the Cornell Library sent a link to an 1806 map of Ithaca. This portion of the map shows "Mill Street" ending near the Markle home and the creek. (It is "Court" street today.)

1806 map of Itnaca, NY
1806 Map of Ithaca, NY Mill Street, Cascadilla Creek, and the Markle home (just north of the creek) are highlighted
After hiking the creek no obvious signs of a mill foundation were found. The one intriguing feature was an apparently artificial cut in the rock near the first waterfall in the creek. This would have been an ideal place for a flume to carry water to a mill farther down the creek.

Firar Waterfall on Cascadilla Creek
First waterfall on Cascadilla reek (Andrews photo)
Indentation in rock at first waterfall
The indentation in the rock in the center of the photo appears to be artificial
(Andrews photo)
Downstream from the first waterfall (closer to Linn street) there is a section of the gorge wall that appears to have been cut to a smooth plane. This could have occurred in 1800 in connection with a mill or it could have been connected with a structure the Treman family built before the land was donated to the city a century later.
Potential site of a mill
Smoothed rock along Cascadilla creek near Linn Street
(Andrews photo)
If there was a mill anywhere along "Mill Street", it would have been below the first waterfall on Cascadilla Creek. The precise location may never be known.