Maryland Route 157 is a state highway located in Baltimore County in the U.S. state of Maryland. The state highway runs 4.79 miles (7.71 km) from MD 158 in Sparrows Point north to North Point Road in Dundalk. MD 157 is an L-shaped highway serves as the primary highway through Dundalk and from Dundalk to Interstate 695 (I-695). The two highways to which MD 157 is assigned, Merritt Boulevard and Peninsula Expressway, were constructed as a four-lane divided county highway in the early 1960s. In the late 1960s, Merritt Boulevard was extended as ramps to I-695 that also serve MD 151 and MD 150. MD 157 was assigned to the highway in Sparrows Point in the early 1990s and extended through Dundalk to its present northern terminus in the late 1990s.

On March 26, 2024, at 1:28 a.m. EDT, the main spans and the three nearest northeast approach spans of the Francis Scott Key Bridge across the Patapsco River in the Baltimore metropolitan area of Maryland, United States, collapsed after the container ship Dali struck one of its piers. Six members of a maintenance crew working on the roadway were killed, while two more were rescued from the river.