The Erie Canal was originally completed in 1825, and enlarged between 1836 and 1862. The "Enlarged Erie Canal" was replaced in 1918 by the 3rd version of the canal, known as the "Barge Canal", and was engineered for powered craft instead of mule-drawn boats. This is the Canal we know today.
Many old structures such as locks and aqueducts from the old versions of the canals still remain, although in various states of repair or disrepair. Many were engineering marvels in their day and all are characterized by the beautiful hand-cut stonework that is still impressive to this day.
Below is a list of traces or remnants of the early canals, almost all of which are of the Enlarged Erie Canal. For additional traces, see also the Travels of Tug 44, New York State Canal History page.
http://www.eriecanal.org/traces.html