Sault Ste. Marie (pronounced Soo' Saint Mare ee) is the oldest city in the U.S. state of Michigan and one of the oldest in the entire United States. It is located in Michigan's Upper Peninsula, on the Canadian border, separated from its twin city of Sault Ste. Marie, Ontario - the oldest city in the Canadian province of Ontario - by the St. Marys River.

The name "Sault Sainte-Marie" is Old French for "Saint Mary's Falls", a reference to the falls and rapids in the Saint Mary's River.

As of the 2000 census, the city had a total population of 16,542. It is the county seat of Chippewa County6.

The city is the site of the Soo Locks which let ships travel between Lake Superior and the lower Great Lakes. Although not as busy as in past years, a considerable amount of domestic and foreign commerce passes through the locks. People come from around the world to view close up the ships passing through the locks. The largest ships are 1,000 feet long by 105 feet wide. Those large ships are domestic carriers (called lakers) that are too large to transit the Welland Canal around Niagara Falls. Therefore, they are land-locked. Foreign ships (termed salties) are smaller.

Sault Ste. Marie is home to Lake Superior State University, founded in 1945 as an extension campus of Michigan Mining and Technological College (now, Michigan Technological University).

Tourism is a major industry in what is usually referred to as the Soo. The locks and nearby casinos are the major draws, as well as the forests, inland lakes and Lake Superior shoreline. It is also a gateway to Lake Superior's scenic north shore through its twin city Sault Ste. Marie, Ontario. The two cities are connected by the large Sault Ste. Marie International Bridge, a steel truss arch bridge with suspended deck passing over the St. Mary's River.

Ojibwa (Chippewa) Native Americans had lived in the area, which they referred to as Baawitigong, for centuries, since it provided an excellent place to catch fish. In 1668, French missionaries Claude Dablon and Jacques Marquette founded a mission, making the Sault the third oldest city in the United States west of the Appalachian Mountains. The falls proved a choke point for shipping. Early Lake Superior ships were hauled around the rapids, much like moving a house, a process which could take weeks. Later cargoes were unloaded and hauled around the radips and loaded onto other waiting boats. The first American locks were built in 1855.