Past the shopping center, business park and the carnival grounds on Twin Arch Road in Mount Airy sits the road’s namesake.
The Twin Arch Bridge was built in 1901 by the Baltimore and Ohio Railroad. The train tracks are situated on top of the bridge. Twin Arch Road runs under one of the arches, while the Patapsco River flows under the other. The bridge is on the border of Carroll and Howard counties, though it is mostly situated in Carroll, according to a 1998 survey completed by the Maryland Historical Trust.
From the survey: “This is the largest and most elaborate stone bridge to survive in Carroll County, and one of the most visible. It is threatened by the proposed widening of Twin Arch Road, since there is only one lane for traffic through the bridge.”
Source: Maryland State Archives website http://msa.maryland.gov/megafile/msa/stagsere/se1/se5/024000/024300/024393/pdf/msa_se5_24393.pdf