Monocacy River
The remainder of Baltimore National Pike from Ridgeville to the Monocacy River was constructed in four sections simultaneously starting in 1953. The first three sections were from west of the Carroll–Frederick county line to the highway's crossing of the Baltimore &amp; Ohio Railroad's main line at a site called Plane No. 4, from there to New Market, and between New Market and Ijamsville Road in Bartonsville. The fourth section was constructed to closely parallel the existing alignment of US 40 from Ijamsville Road in Bartonsville to just east of the Monocacy River. All four sections opened as a divided highway with a macadam surface in 1955. The following year, Baltimore National Pike from Ridgeville to the Monocacy River was completed with an asphalt surface. The final section of Baltimore National Pike, from east of the Monocacy River to the east end of Patrick Street near modern Exit 56, was expanded to a divided highway in 1953 with the exception of the Monocacy River crossing. Engineering work on a second bridge across the Monocacy River began in 1954. The new bridge, which would complement the existing bridge that had been constructed in 1944 to replace the historic Jug Bridge, opened in 1956, completing the Baltimore National Pike.