How were canals built in the 1800s(U.S. canals)?

Question

How long did it take and how many people it took?

Answer 1

~Most of them were dug. A few were pre-fabbed at the Hartwick, Rhode Island canal factory and then shipped by oxcart to the desired location, laid out and filled with water. Unfortunately, quite a number of the Hartwick pre-fabs were situated such that only one end connected to a waterway and they were thus useless. These later became the core of municipal sewage disposal systems.

Answer 2

usually by hand. lots of men, lots of shovels.