According to the Environmental Protection Agency, Lake Ontario is the farthest east of all the Great Lakes. The National Oceanic and Atmospheric Administration identifies Ontario as the smallest of those five lakes, just behind its next-door neighbor, Lake Erie.
Lake Ontario has a surface area of 9,910 square miles, while Lake Erie's is more than twice that amount. However, the EPA points out that Lake Ontario has a greater volume than Lake Erie. NOAA states that Ontario has a volume of 393 cubic miles, while Erie's is just 116 cubic miles. The average depth of Lake Ontario is 283 feet, and it extends 802 feet down at its deepest point.