Known as Dublin Road, the state highway runs 5.65 miles (9.09 km) from MD 543 in Ady east to U.S. Route 1 (US 1) near Dublin.

The state highway heads east as a two-lane undivided road through farmland.

MD 440 passes by the forested Scarboro Conservation Area and passes through the hamlet of Scarboro before intersecting MD 136 (Whiteford Road) in the village of Dublin.

The state highway crosses Peddler Run before reaching its eastern terminus at US 1 (Conowingo Road) between Dublin and Darlington.

[3][4] The state highway was extended east to US 1 in 1956.