It is a township which was near Hamilton. Hamilton has swallowed up some of it now. That area was given to Loyalists (UELs) before the War of 1812 to act as a buffere between the US and CA. The US was indeed repelled when they sought to annex the ismiss.

A map of Salffleet in the mid 19th century can be found here.
http://digital.library.mcgill.ca/countyatlas/SearchMapframes...

It has the owners of large parcells listed so you might find his ancestor on the map.