It is just over 419 miles (674 km) in length, making it the longest state highway in South Dakota.

When first implemented in 1926, the western terminus was at South Dakota Highway 45 near Gann Valley.

A further extension westward occurred in February 1961, when SD 34 absorbed the alignment of South Dakota Highway 24.

[5] In the late 1960s, a portion of SD 34 (along with U.S. Highway 14) was upgraded as part of the construction of Interstate 90.

This is part of a 4-lane route from Huron to Mitchell via South Dakota Highway 37.