At the apex of its length in the 1950s, M-47 stretched from Webberville in the south to Bay City State Park in the north.

Since Interstate 75 (I-75) opened in the Tri-Cities area, the northern section of M-47 was rerouted and truncated as a result of related changes to other highways.

[3][4] As part of its maintenance duties, the Michigan Department of Transportation (MDOT) tracks the volume of traffic on the highways it maintains.

[5] Additionally, the entire route of M-47 has been listed on the National Highway System,[6] a network of roads important to the country's economy, defense, and mobility.

[12][13] M-47 replaced the remainder of M-111 and extended southward from the park to Bay City in 1938, creating a "U-turn" in the routing.

[16][17] At its greatest extent in the 1950s, the highway extended north from Webberville through Owosso and St. Charles to a junction with M-46 between Hemlock and Shields.

M-47 then ran separately to the state park before turning south and back into downtown Bay City, ending at the US 23 business loop.

[18] Major changes to the routing of M-47 started in December 1960 when the I-75/US 10/US 23 freeway opened between Saginaw and Bay City.

[24][25] The interchange at Salzburg Road north of Freeland opened in 1970, and the expressway segment was upgraded to a full freeway.

[25][26] In the end, only about a mile and a half (2.4 km) of roadway still bears the M-47 from before the changes made starting in 1960,[3][18] along a section of road that was not originally part of the highway in 1919.