Radium is an unincorporated community in section 19 of Comstock Township, Marshall County, Minnesota, United States.

Marie Railroad (Soo Line Railroad) branch line built in 1905 from Thief River Falls, Minnesota, to Kenmare, North Dakota.

It is also on the Warren telephone exchange and part of the Warren-Alvarado-Oslo school district.

There is still a large grain elevator on the railroad line south of the townsite.

A small Lutheran church 1+1⁄2 miles (2.4 km) south of the town antedates the coming of the railroad; Immanuel Lutheran Church (LCMS) was organized in 1897.