 = Route 261 ( Delaware – Pennsylvania ) = 
 
 Delaware Route 261 ( DE 261 ) and Pennsylvania Route 261 ( PA 261 ) , also known as Foulk Road , is a 6 @.@ 88 @-@ mile ( 11 @.@ 07 km ) state highway running through Delaware and Pennsylvania . DE 261 runs 4 @.@ 62 miles ( 7 @.@ 44 km ) through New Castle County , Delaware from an interchange with U.S. Route 202 ( US 202 ) and DE 141 north of Interstate 95 ( I @-@ 95 ) near Fairfax , Delaware , a community north of Wilmington , northeast to the Pennsylvania state line . The road runs through suburban areas of Brandywine Hundred as a four @-@ lane road south of DE 92 and a two @-@ lane road north of DE 92 . At the Pennsylvania state line , Foulk Road becomes PA 261 and continues 2 @.@ 26 miles ( 3 @.@ 64 km ) through Bethel Township in Delaware County , intersecting PA 491 in Booths Corner before ending at an interchange with US 322 . 
 DE 261 was originally designated along Foulk Road in the 1930s . In the 1960s , most of the route was widened into a four @-@ lane road . The southern terminus at US 202 was reconstructed into an interchange in the 2000s . PA 261 was first designated in 1928 along Foulk Road between the Delaware border and PA 61 and PA 161 in Chelsea . The route was extended north along Valley Brook Road to US 1 in Chester Heights by 1940 . The northern terminus of PA 261 was moved to its current location by 1980 . 
 
 = = Route description = = 
 
 
 = = = Delaware = = = 
 
 DE 261 begins at an interchange with US 202 and the northern terminus of DE 141 north of Alapocas Run State Park near Fairfax , heading northeast on four @-@ lane divided Foulk Road . The road heads near business parks , becoming an undivided road . The route continues through the suburban Brandywine Hundred area , passing residences along with a few businesses . DE 261 remains a four @-@ lane undivided road through this area , occasionally widening into a divided highway at intersections . The route intersects several roads including Murphy Road , Shipley Road , and Silverside Road . Between Shipley and Silverside roads , the road passes to the west of Brandywine High School . Farther northeast , DE 261 comes to the intersection with DE 92 , at which point it turns north and becomes a two @-@ lane undivided road that passes more homes . The route ends at the Pennsylvania state line . 
 DE 261 has an annual average daily traffic count ranging from a high of 22 @,@ 555 vehicles at the Silverside Road intersection to a low of 10 @,@ 414 vehicles at the Pennsylvania border . None of DE 261 is part of the National Highway System . 
 
 = = = Pennsylvania = = = 
 
 PA 261 begins at the Pennsylvania state line and continues northeast on two @-@ lane undivided Foulk Road through Bethel Township in Delaware County , passing through residential areas as it crosses Zebley Road . In the community of Booths Corner , PA 261 crosses PA 491 , at which point the road passes a few businesses . North of this intersection , the road runs between a tank farm to the west and Bethel Springs Elementary School to the east prior to crossing Bethel Road and entering wooded residential neighborhoods . PA 261 ends at an interchange with US 322 , with Foulk Road continuing north to an intersection with Concord Road , Chelsea Road , and Valley Brook Road . 
 PA 261 has an annual average daily traffic count ranging from a high of 9 @,@ 400 vehicles between the Delaware border and PA 491 to a low of 7 @,@ 200 vehicles between the Bethel Road intersection and US 322 . None of PA 261 is part of the National Highway System . 
 
 = = History = = 
 
 
 = = = Delaware = = = 
 
 By 1920 , what is now DE 261 existed as a county road . When Delaware first assigned state highway numbers by 1936 , what is now DE 261 had been upgraded to a state highway , but did not receive a number at that time . By 1938 , DE 261 was designated onto its current alignment between US 202 and the Pennsylvania border , continuing the PA 261 designation . DE 261 was widened into a four @-@ lane road between US 202 and Silverside Road by 1966 . The four @-@ lane portion was extended north to Naamans Road a year later . In summer 2007 , construction on converting the intersection with US 202 into interchange was completed as part of the Blue Ball Properties project , a project undertaken to improve roads in this area as part of AstraZeneca locating their North American headquarters to the area . DE 141 was also realigned to intersect US 202 and DE 261 at this interchange . The total cost of the project was $ 123 million . 
 
 = = = Pennsylvania = = = 
 
 When Pennsylvania first legislated its highways in 1911 , what would become PA 261 was legislated as part of Legislative Route 180 between the Delaware border and Chelsea . PA 261 was first designated in 1928 to run from the Delaware border to PA 61 ( Concord Road ) and PA 161 ( Chelsea Road ) in Chelsea , following Foulk Road . By 1940 , PA 261 was extended north along Valley Brook Road from US 322 ( which replaced PA 61 ) to US 1 in Chester Heights . By 1980 , the northern terminus of PA 261 was truncated to its current location at the interchange with US 322 . 
 
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