Minnesota State Highway 84 (MN 84) is a 29.865-mile-long (48.063 km) highway in north-central Minnesota, which runs from its intersection with Highway 371 in Pine River and continues north to its northern terminus at its intersection with State Highway 200 in Kego Township, four miles north of Longville.

The route is two lanes throughout except for a small portion in Pine River near its southern terminus at Highway 371.

The route is a winding road with several sharp turns of 25 mph (40 km/h) or less.

State Highway 84 serves as a north–south route between the communities of Pine River and Longville in north-central Minnesota.

Highway 84 has a junction with the eastern terminus of State Highway 87 about midway between Pine River and Longville.