Darlington is an unincorporated community and census-designated place in northeastern Harford County, Maryland, United States. The population was 409 at the 2010 census. The center of the community was listed on the National Register of Historic Places as the Darlington Historic District in 1987. Median household income is $66,563. The percentage of people in poverty is 5.3%.
Darlington is located in northeastern Harford County at 39°30′10″N 76°19′8″W (39.502757, −76.318971), along Maryland Route 161. U.S. Route 1 crosses the northern side of the community, leading northeast 65 miles (105 km) to Philadelphia and southwest 35 miles (56 km) to Baltimore. Route 1 crosses the Susquehanna River at Conowingo Dam, 2 miles (3 km) northeast of Darlington. Havre de Grace is 11 miles (18 km) to the southeast via Routes 161 and 155.
According to the United States Census Bureau, the Darlington CDP has a total area of 1.05 square miles (2.72 km2), all land.
The southern part of the CDP, south of Shuresville Road, is part of the Darlington Historic District, listed on the National Register of Historic Places (NRHP) in 1987.