DE 42 begins at an intersection with DE 6 in Blackiston. Northwest of DE 6, the road becomes Longridge Road, which changes names to Delaney Maryland Line Road and Clayton Delaney Road before it reaches the Maryland border and becomes Maryland Route 330. MD 330 heads west into Kent County, Maryland and, by way of MD 313, provides access to US 301. From the western terminus, DE 42 heads southeast on two-lane undivided Blackiston Road. The route runs through agricultural areas with some woods and homes. The road reaches the town of Kenton, where it becomes Commerce Street. In Kenton, the route crosses an abandoned railroad line and passes residences and a few businesses, intersecting with DE 300 in the center of town. Past Kenton, DE 42 heads to the east-southeast on Seven Hickories Road into farmland with woods and residences, crossing Pinks Branch. In Seven Hickories, the route intersects DE 15 and the two routes head east for a concurrency. In Moores Corner, DE 15 splits from DE 42 by turning southeast on Kenton Road before DE 42 continues east and intersects Pearsons Corner Road. The road heads east-northeast and passes to the south of Delaware Airpark. The route enters the town of Cheswold, where it becomes Main Street. The road passes homes and some businesses in the town, crossing the Delmarva Central Railroad's Delmarva Subdivision line at-grade. DE 42 reaches an intersection with US 13 on the eastern edge of Cheswold at Bishops Corner. After the US 13 intersection, the route heads northeast on Fast Landing Road. DE 42 passes over the DE 1toll road, where it has ramps for emergency vehicles but no public access. The road runs through farmland with some woodland and homes, curving to the east. Farther east, the route turns southeast into marshland adjacent to the Leipsic River, crossing Dyke Branch. DE 42 enters the town of Leipsic, where it heads east into residential areas and ends at DE 9. Past the eastern terminus, the road continues east as Second Street. DE 42 has an annual average daily traffic count ranging from a high of 7,654 vehicles at the eastern border of Cheswold to a low of 536 vehicles at the eastern terminus at DE 9. None of DE 42 is part of the National Highway System.
History
By 1920, what is now DE 42 existed as an unimproved county road. The road was completed as a state highway between Kenton and Lepisic four years later. The route was under construction as a state highway between Blackiston and Kenton by 1932. By 1936, DE 42 was assigned to its current alignment between DE 300 in Kenton and DE 9 in Leipsic and the state highway between Blackiston and Kenton was completed. By 1966, the route was extended to Blackiston.
