Darlington Township was formed in 1847 from Little Beaver Township, taking its name from the borough which it surrounds. Two years later, Lawrence County was formed cutting through Little Beaver Township and leaving only a narrow strip in Beaver County. This land was added to Darlington Township.
The history of the township is closely associated with the of Darlington Borough, and many of the homes and landmarks associated with the latter are in the township. Foremost among these is the Darlington Reformed Presbyterian Church, founded in 1847 as the Darlington Free Presbyterian Church by Arthur Bradford over the question of slavery. The Bradford house is located a few miles to the north, and is owned by a descendant. On the grounds is one of three brick "prophet's chambers" in the township; these were small, two-story retreats designed to give visiting preachers the isolation necessary to study and write sermons.
The township (along with the borough) developed with every advantage of transportation. Originally on the Sandusky Indian Trail, this route became the main road between Pittsburgh and Cleveland. Greersburg village became a stage coach stop and freight terminal. Ten years after incorporation , the borough changed its name to Darlington, on the suggestion of a Pittsburgh merchant of that name.
The Ohio and Pennsylvania Railroad, built in 1851, dealt a serious blow to Darlington in bypassing the village. A rival community, New Galilee, grew up three miles away on the railroad. In time, however, a connecting line, the Pittsburgh, Lisbon and Western Railroad, was built along Little Beaver Creek connecting Lisbon, Ohio with Cannelton, Darlington, and New Galilee. This line still serves Darlington, but the connection to the main line (now Conrail) at New Galilee has been abandoned.
Enon Valley Borough, on the township's northern boundary, also became an important station on the main line, with connections to New Castle and significant benefits to Darlington Township.
The Cannelton area has an interesting history. Near here, in the 1750's, the Iroquois Half-King Tanacharison had a hunting camp. When George Washington came to Logstown in 1753, a messenger was sent to Tanacharison at his lodge to summon him for a conference with the young emissary from Virginia. In the 1830's, a vein of cannel coal (originally "candle" coal) was discovered, and mining soon began on an intensive scale. Cannel coal is rich in hydrocarbons and burns readily with a bright flame. The popularity of this coal led to the construction of the Darlington Cannel Coal Railroad and the development of the township's first major industry. Ira Mansfield obtained a controlling interest in the mines and under his influence, the industry reached peak production. The Mansfield homestead still stands near Cannelton village. In later years, clay mining replaced that of coal, and a clay grinder was built here, but is now abandoned with the decline of brick production. In the 1960's, the A.I.D. Industrial Park (Area Industrial Development Council) was established, and a number of diversified industries have been attracted to the area.
The superior quality of fire clay in the township led to the establishment of several major brick yards in the area. Two of these are still in production in the township.
An important local landmark is the Darlington Polo Grounds, one of very few with overhead lighting for night matches. Darlington Township is a member of the Blackhawk School District.