US 33 terminated at a five-ramp partial cloverleaf interchange with US 12 (Pulaski Highway) south of the city of Niles in Bertrand Township.

[5][6] According to the Michigan Department of Transportation (MDOT), the agency that maintained the roadway, in 1998, the last year it was US 33, the highway carried between 17,192 and 24,669 vehicles on average, daily.

[13] When the United States Numbered Highway System was created on November 11, 1926,[14] the corridor received the US 31 designation.

[15] The US 33 designation was later added to US 31 from the state line northward to St. Joseph on January 1, 1938,[2] ending at the intersection with US 12/US 31 at Main Street and Niles Avenue.

[17] In November 1960, the US 33 designation was extended northward along US 31 from St. Joseph through Benton Harbor to Hagar Shore Road in Lake Michigan Beach.

[20][21] US 33 was all but eliminated in Michigan on June 9, 1986, when the American Association of State Highway and Transportation Officials (AASHTO) approved a request by MDOT to truncate the designation to the intersection with US 12 south of Niles.

[24] Otherwise, except for a slight reroute at Scottdale,[25] all of US 33 at its greatest extent from 1963 through 1986 remains part of a state highway in Michigan.