240 across the railroad. US 240 continued north from Gaithersburg across Great Seneca Creek to the hamlets of Middlebrook and Neelsville. In the latter location, the highway met the northern end of MD 118 (Germantown Road) at what is now Boland Farm Road and the southern end of MD 27 (Ridge Road) at what is presently Henderson Corner Road. US 240 crossed Little Seneca Creek and had a pair of staggered intersections with MD 121 (Clarksburg Road); the latter highway followed what are now Spire Street and Redgrave Place north and south, respectively. The U.S. Highway crossed Little Bennett Creek just south of the village of Hyattstown, where the highway intersected Old Hundred Road; MD 109 did not yet extend to Hyattstown. Just north of Hyattstown, US 240 crossed the Montgomery–Frederick county line and met the southern end of MD 75 (Green Valley Road). US 240 crossed Bennett Creek as it approached Urbana, through which the highway ran concurrently with MD 80 (Fingerboard Road). The U.S. Highway descended into the valley of the Monocacy River, which the highway crossed just south of its bridge across the Old Main Line of the Baltimore & Ohio Railroad at Frederick Junction. South of the city limits of Frederick, US 240 had an oblique intersection with US 15 (Buckeystown Pike) just south of the modern intersection of MD 355 and MD 85. US 15 and US 240 entered Frederick together along Market Street. The U.S. Highways crossed Carroll Creek before US 240 ended at US 40 (Patrick Street) in the center of downtown Frederick. US 15 continued north along Market Street toward Gettysburg. History U.S. 240's original route between Maryland Route 109 and Maryland Route 85 (then part of U.S. 15) was supplanted by a new freeway alignment in 1953; U.S. 240 was diverted away from its original route onto the new freeway as it was completed south to the future alignment of the Capital Beltway. In 1956, with the arrival of the Interstate Highway System, the route gained the designation Interstate 70S (now Interstate 270). In Maryland, the whole of U.S. 240 was redesignated as Maryland Route 355 around 1970. U.S. 240 crossed into Washington, D.C. on Wisconsin Avenue, it turns southwest onto Massachusetts Avenue (Washington, D.C.) and then south-southwest onto Connecticut Avenue at Dupont Circle. It reached U.S. Route 50 at K Street and by 1968 extended to the area around the