M-34 is an east–west state trunkline highway in the southeastern region of the US state of Michigan. It has a western terminus near Osseo on M-99 and runs through forest and farm lands to its eastern terminus at Business US Highway 223 and M-52 in Adrian. The highway serves a number of smaller communities in the area and intersects two US Highways while carrying between 4,200 and 11,300 vehicles on a daily basis.

Osseo is an unincorporated community in Hillsdale County in the U.S. state of Michigan. The community is located along M-34 within Jefferson Township.