M-125 starts at the state line as the continuation of Detroit Avenue running northward from Toledo.

Once across the state line, the roadway takes on the Dixie Highway name and passes a residential subdivision.

The highway runs north-northeasterly roughly parallel with, and between, both US 24 and I-75 through farm land in rural Monroe County.

About five miles (8.0 km) north of Monroe, after running through farm land again, M-125 terminates at an intersection where Dixie Highway merges into US 24 (Telegraph Road).

[6] No section of M-125 has been listed on the National Highway System,[7] a network of roads important to the country's economy, defense, and mobility.

[8] M-125 was first designated on a road in the Upper Peninsula from US 2 to north of Thompson in 1931;[9][10] this roadway was later merged into M-149 in 1936 after a rerouting of US 2 through the area.

[11][12] Later in 1938, the M-125 designation was used for a highway under construction along Parish Road in Bay County running for three miles (4.8 km) west of US 23 (now M-13).

[18][19] The Dixie Highway was conceived in 1915 to connect Chicago to Miami and commemorate a half-century since the end of the Civil War.