MD 136 begins at an intersection with MD 7 (Philadelphia Road) east of Abingdon at the edge of Bush Declaration Natural Resources Management Area, just north of the confluence of Bynum Run and James Run to form the Bush River.

The junction is near the site of the signing of the Bush Declaration, a 1775 resolution of Harford County citizens that supported the activities leading up to American Revolution.

MD 136 heads north through farmland as two-lane undivided Calvary Road, which crosses over Interstate 95 (I-95, John F. Kennedy Memorial Highway) with no access.

[1][2] North of Creswell, MD 136 passes to the west of Stoney Demonstration Forest, crosses Broad Run adjacent to a quarry in the hamlet of Calvary, and passes close to the historic home Webster's Forest, which is accessed via Asbury Road.

The state highway traverses Deer Creek at Priest Ford, which is the site of Priest Neal's Mass House and Mill Site, a historic church, and a junction with Harmony Church Road, which leads through the Lower Deer Creek Valley Historic District.

Whiteford and the neighboring village of Cardiff are part of the Whiteford-Cardiff Historic District, which preserve buildings from the 19th century when the area was a center of the slate industry.

In 1933, MD 136 achieved its original extent when the state highway was extended north from Whiteford to Graceton.

[13] The state highway reached its current extent in 1956 when the county highway between Graceton and Five Forks was transferred to state control; MD 136 was extended southwest to Five Forks then assumed all of MD 517 to its present northern terminus in Norrisville.