 During World War II, MD 151 was extended north through Dundalk on a new divided highway parallel to MD 20 and through East Baltimore on an expanded Erdman Avenue to connect the Bethlehem Steel complex at Sparrows Point with MD 150 and US 40.In the late 1960s and early 1970s, Interstate 695 (I-695) was constructed parallel to MD 151 between Edgemere and MD 157 in Dundalk.MD 151 begins at an intersection with 7th Street within the former Bethlehem Steel complex.