PA 841 begins at the Maryland border in the community of Lewisville in Elk Township, Chester County, where the road continues south into that state as MD 213. From the state line, the route heads north on two-lane undivided Chesterville Road, intersecting the southern terminus of PA 472 a short distance past the state line. The road continues north through a mix of farms and woods with some homes, crossing the Big Elk Creek into New London Township. The route turns to the east and enters Franklin Township, where it curves to the northeast. PA 841 comes to an intersection with PA 896 and continues through rural areas with some residences. In the community of Chesterville, the route turns northwest onto Wickerton Road. PA 841 curves to the north and heads into London Grove Township as it continues through rural land with increasing residential subdivisions. The road enters the borough of West Grove and becomes Prospect Avenue, where it is lined with homes. In the center of town, the route passes a few businesses and crosses an East Penn Railroad line at-grade. PA 841 turns east onto Evergreen Street and curves northeast past residences and commercial establishments. The route splits from Evergreen Street by heading north onto Chatham Road. PA 841 leaves West Grove for London Grove Township again and comes to an interchange with the US 1 freeway. The road continues into a mix of farmland and woodland with occasional homes. In the community of Chatham, the route turns east onto London Grove Road and comes to a junction with PA 41. Past PA 41, PA 841 turns north onto Coatesville Road and continues north through agricultural areas with a few homes, reaching an intersection with PA 926. Upon crossing PA 926, the road heads into West Marlborough Township on North Chatham Road and makes a curve to the northwest through farmland and woods. The route intersects the western terminus of PA 842 and makes a curve to the north before bending to the northeast. PA 841 continues north to the community of Springdell, where it makes a sharp curve to the east. The route curves northeast through farmland and continues to its northern terminus at PA 82 in the community of Doe Run.
History
When Pennsylvania first legislated routes in 1911, present-day PA 841 was not given a route number. In 1928, PA 841 was designated onto an unpaved road running from Springdell northeast to PA 82. In 1937, PA 841 was extended south from Springdell to its current southern terminus at the Maryland border, following its current alignment. By 1940, the entire length of the route was paved. PA 841 has remained along the same alignment since.
Major intersections
PA 841 Alternate Truck
Pennsylvania Route 841 Alternate Truck is a truck route bypassing a weight-restricted bridge over a branch of the West Branch of White Clay Creek in Franklin Township, on which trucks over 35 tons are prohibited. Formed in 2013, it follows PA 896, PA 796, Baltimore Pike, and Evergreen Street.