The Bullfrog Road Bridge was built in 1908 by the York Bridge Company out of York, Pennsylvania. It was eventually listed on the National Register for Historic Places in 1978. It connects Frederick and Carroll Counties over the Monocacy River.
As many of the historic bridges in the area are that of the wood covered variety, this one stands out as it is one out of two in Frederick County that has a steel truss design. Specifically, this design is of the Parker truss variety, which means that the top chord is a polygon arc. This bridge received updates in 1989 (new abutments) and in 1995 (span).