Lake Sidney Lanier
Define "land locked harbor". Is the Port of San Francisco "land locked"? If the fact that it's on a bay that is DIRECTLY connected to the ocean means you don't consider it "land locked", then how about the Port of Chicago, which is on a lake, but with a navigable path to the sea both via the St. Lawrence Seaway and the Mississippi River, along with assorted canals and locks? The Great Salt Lake Marina is pretty definitely land locked, but I'm not sure it counts as a "harbor" since I don't think there's any shipping through it.The term "largest land locked harbor" is essentially meaningless unless a specific definition of "land locked harbor" is included.
UTAH
Lake Powell
The largest lake in the US is Lake Superior and its maximum depth is 1,332 ft.
In the US, Lake Superior is the largest lake. Lake Michigan is the largest lake that is actually in the US. Lake Superior is larger but it's impossible to credit it as largest since a good deal of it is in Another Country, namely Canada.
The Caspian Sea is the largest lake in the world at 143,244 square miles. Though it is saltwater, it is land-locked. The largest freshwater lake in the world is Lake Superior at 31,700 square miles. Lake Baical in Russia has the largest freshwater volume in the world at 23,600 km3 (5,700 cu mi), and is also the deepest at 5,370 ft. (Deeper than the Caspian.) The Caspian Sea is connsidered to be the largest lake on Earth, but is salt water. The largest fresh water lake is Lake Superior which borders the USA and Canada (and is part of the Great Lakes). (The Caspian Sea borders Russia, Kazakhstan, Iran, Azerbaljan and Turkmenistan.Lake Superior is the largest freshwater lake according to its size in area. Lake Baikal is the largest freshwater lake according to its volume of water.
Lake Superior
Lake Superior
Lake Superior
Lake Michigan
The largest lake in the US is Lake Superior, one of the great lakes, on the Canadian border (it's partially in the US and partially in Canada).
Your question assumes the Great Salt Lake is the largest lake in the US. It is not. That would be Lake Superior.