Saginaw (/ˈsæɡɪnɔː/) is a city in Saginaw County, Michigan, United States, and its county seat. It had a population of 44,202 at the 2020 census. Located along the Saginaw River, Saginaw is adjacent to Saginaw Charter Township and considered part of Greater Tri-Cities region of Central Michigan. The Saginaw metropolitan area had a population of 190,124 in 2020, while the Tri-Cities area had 377,474 residents.

Established as a fort following the 1819 Treaty of Saginaw, Saginaw was a thriving lumber town in the 19th century. It was an important industrial city and manufacturing center throughout much of the 20th century due to its automobile and automotive parts production led by General Motors. As part of the Rust Belt, its industry and strong manufacturing presence declined, leading to increased unemployment, crime, and a population decline. Modern economic development is focused on comparative advantages in innovation, clean energy, and continued manufacturing exports. However, the city continues to have a higher proportion of manufacturing jobs than the U.S. average.

The name Saginaw is widely believed to mean "where the Sauk were" in Ojibwe, from Sace-nong or Sak-e-nong (Sauk Town), due to the belief that the Sauk once lived there. But it is more likely that the name means "place of the outlet", from the Ojibwe sag (opening) and ong (place of).

When Natives told Samuel de Champlain that the Sauk nation was on the western shore of Lake Michigan, Champlain mistakenly placed them on the western shore of Lake Huron. This mistake was copied on subsequent maps, and future references identified this as the place of the Sauks. Champlain himself never visited what is now Michigan.

The site of what later became the city of Saginaw was originally inhabited by the Anishnabeg. French missionaries and traders first appeared in the area during the late 17th century and encountered the Ojibwe (Chippewa) living in the area. The first permanent settlement by those other than Native Americans was in 1816 when Louis Campau established a trading post on the west bank of the Saginaw River. Shortly thereafter the United States established Fort Saginaw. Campau's trading post was also inhabited by Metis.

During Michigan's territorial period, a county and township government were organized at Saginaw. Growth of the settlement was fueled rapidly during the 19th century by the lumber industry. Saginaw was the site of numerous sawmills and served as a port for Great Lakes vessels. What is now the city of Saginaw resulted from the consolidation of the cities of East Saginaw and Saginaw City (West Side) in 1889.

In 1819, Lewis Cass, in the Treaty of Saginaw, negotiated the prerogative for the United States to own and settle the area with the leaders of the Ojibwe. In 1820, Campau attempted to expand across to the east bank of the river but was rejected by the Chippewas. In 1822, the United States Army established a fort on the west bank of the Saginaw River and named it Fort Saginaw. Two companies were stationed at the fort. A group of investors purchased some land near the fort and had it platted under the name, Town of Sagana. Due to the extremely harsh seasons and illnesses, Fort Saginaw was abandoned by 1824.

By the late 1820s, the American Fur Company was operating a post at Saginaw.