Lake Erie is the Southernmost of the North American Great Lakes.
Lake freighters and other vessels do not need to go through canal locks when proceeding downstream from Lake Huron. They do need to go through a series of locks to travel downstream from Lake Erie to Lake Ontario, through the Welland Canal.
Lake Erie is the second largest of the North American Great Lakes by surface area, being slightly larger than Lake Ontario. But Lake Ontario is deeper, so, of the five lakes, it is the lake with the smallest volume.
Buffalo is the largest city in New York State on the Lake, and the terminus of the Erie Canal. The first Erie Canal was built prior to the construction of the North American railroad grid, and its route through the mountains on the United States's East coast was the first affordable path for the transportation of freight across the Mountains to the United States interior.
Erie is the largest city on Pennsylvania's Lake Erie coast.