The middle section of MD 439 was brought into the state highway system around 1980.

The state highway heads east as a two-lane undivided road through a four-ramp partial cloverleaf interchange with I-83 (Baltimore–Harrisburg Expressway).

MD 439 heads southeast and passes through the hamlet of Shane as the highway follows the height of land between the drainage basins of Little Gunpowder Falls and Deer Creek.

Shortly after crossing the Baltimore–Harford county line, the state highway reaches its eastern terminus at MD 23 (Norrisville Road) in Shawsville.

MD 439 was relocated when I-83 was completed from Parkton to the Pennsylvania state line in 1959.