The city shares common borders with Essexville and the townships of Bangor, Frankenlust, Hampton, Merritt, Monitor, and Portsmouth.

[citation needed] The Post Office changed its name to Bay City on March 22, 1858.

Many of the early pioneers moved to Lower Saginaw as it became clear its deeper waters made it a better location for the growth of industry which relied on shipping.

By 1860, Lower Saginaw had become a bustling community of about 2,000 people with several mills and many small businesses in operation.

Rapid economic growth took place during this time period, with lumbering, milling, and shipbuilding creating many jobs.

The early industrialists in the area used the Saginaw River as a convenient means to float lumber to the mills and factories and as a consequence amass large fortunes.

[8] During the latter half of the 19th century, Bay City was the home of several now-closed industries including many sawmills and shipyards.

At the outbreak of the First World War, Bay City contained a largely German neighborhood called Salzburg.

The Salzburghers demanded that the rest of Bay City recognize them as Americans first and German-American second but hostility towards them continued.

[10] The governor of Michigan at the time, Albert Sleeper, sought support from the German-American community but experienced backlash.

The following morning, when the swing span was operated, one half crashed into the Saginaw River blocking all riverine traffic.

[12] The Wenonah Hotel was located at the corner of Center Ave and Water Street, the current site of the Delta College Planetarium.

On Christmas Eve, 1979, a large Bay City department store of long standing, Oppenheim's, was destroyed by fire.

A passing cargo ship, MV Buffalo, moving at excessive speed, created a wake that caused Jupiter to break free of its berth.

There was considerable legal action taken, ultimately resulting in an adjudication that was subsequently appealed by the owners of Buffalo.

The findings of the Court of Appeals upheld the original decision, which assigned 50% of the responsibility to Buffalo (for her excessive speed), 25% to the dock operator (for rotten wood pilings) and 25% to Jupiter (for improper procedures in unloading her cargo).

The Bay City Electric Light and Power policy was to install the limiter, and to notify the customer by trying to collect the amount due.

[19] The day following his death, Bay City Electric Light and Power removed the limiters from all households.

It was later learned that Schur had willed his estate, estimated by his family to be in excess of $500,000, to Bay Regional Medical Center.

[20] On October 12, 2010, the historic 113-year-old City Hall sustained significant damage as the result of an attic fire which caused the sprinkler system to run for nearly two hours.

Bay City is sometimes regarded as being part of the greater Thumb of Michigan Area, which is also a sub-region of the Flint/Tri-Cities.

Bay City is well known in Mid-Michigan for its numerous festivals and celebrations which take place during the summer months.

The Bay County Historical Museum, located on Washington Avenue, is the designated repository for the records of the Patrol Craft Sailors Association and also contains numerous displays on local and regional history.

[33] Bay City is the home to the Tri-City Ice Hawks of the United States Premier Hockey League.

Following the resignation of 7th Ward Commissioner Shelley Niedzwiecki,[45] Christopher Runberg was appointed by the Commission to serve the remainder of her term.

Four modern bascule bridges allow transportation across the Saginaw River, which separates the East and West sides of Bay City.

[59][60] Many residents have expressed complaints about the sale and tolling of the bridges, citing a lack of transparency and willingness to work with other branches of government from the city.

[67] The singer Madonna, who was born in Bay City, referred to her birthplace as "a little, smelly town in Northern Michigan" for which she has had great affection on national television.

[68][69] Mike Buda, former Mayor in the 1990s, commented: "Madonna was absolutely right", explaining that air pollution from the gas refinery and a neighboring beet sugar plant was in fact so bad that the EPA forced the industries involved to pay a cash settlement to families, like those of Madonna's grandmother Elsie Fortin, with homes in the Banks neighborhood.

[70] The story of Bay City's refusal to have a commemoration sign about the singer was described in a book Madonnaland (2016) by Alina Simone.