Known as Lillian Street, the state highway runs 1.48 miles (2.38 km) from MD 347 east to U.S. Route 50 (US 50) within Hebron in western Wicomico County.

The two-lane undivided state highway heads southeast through the town, then turns east after passing Chestnut Tree Road and leaves the town limits.

MD 670 continues east through farmland until its eastern terminus at US 50 (Ocean Gateway).

Traffic heading eastbound on MD 670 is required to turn onto US 50 east; US 50 west can be accessed via a crossover in the divided highway a short distance to the east.

[3][4] Direct access between eastbound MD 670 and westbound US 50 was removed in 2007.