M-39 is a north–south state trunkline highway in Metro Detroit area of the US state of Michigan that runs from Lincoln Park, on the south end, to Southfield on the north. The official southern terminus of M-39 is at the corner of Southfield Road and Lafayette Boulevard in Lincoln Park, one block southeast of the junction of Interstate 75 (I-75, Fisher Freeway) and two blocks northwest of M-85 (Fort Street). From there the highway heads northward. The first of the highway follows Southfield Road, a divided highway in the Downriver area. It then transitions into the Southfield Freeway, which is a freeway that runs from Allen Park north through Dearborn, and then the west side of Detroit, to Southfield. The northern terminus is at M-10 (Lodge Freeway) in Southfield. The current M-39 is the third highway to bear the designation. The first dated back to the origins of the state highway system in 1919 and ran between Grand Rapids and Lansing. This highway was replaced in segments through the 1920s and 1930s by realignments or extensions of other highways in the area. The second was part of Schaefer Highway in the Detroit area from 1939 until the end of the 1950s. The current highway was commissioned when the M-39 designation was moved to Southfield Road from Schaefer Highway. During the 1960s, it was converted into a freeway in stages. Afterwards, it was extended to end at M-85 (Fort Street) before a change in the 1980s gave the trunkline its present termini. Route description M-39 begins at Lafayette Boulevard a block east of its junction with I-75 in Lincoln Park along Southfield Road, which continues east-southeasterly past the start of the M-39 designation under local maintenance. From there the road is a six-lane boulevard through residential areas as it runs west-northwesterly to pass under I-75 and an adjacent Conrail Shared Assets Operations rail line. In Allen Park, the highway continues through residential and commercial areas. Southfield Road crosses lines of the Canadian National Railway and Norfolk Southern Railway near the location where the highway turns to the northeast and transitions into a six-lane limited-access freeway. Immediately after this transition, the Southfield Freeway, as M-39 is now called, has an interchange with I-94. There is a second, adjacent interchange that connects to Van Born Road, and the freeway winds its way northeasterly through Dearborn. The freeway is bordered by service drives that