Jarrettsville is an unincorporated community and census-designated place (CDP) in Harford County, Maryland, United States.

In 1771, Abraham Jarrett was granted 2,380 acres of land near the falling branch area to which was used for the production of hogshead barrels mainly used for the transportation of tobacco.

[5] My Lady's Manor was listed on the National Register of Historic Places in 1978, and includes portions of Jarrettsville.

[9] Maryland Route 23 passes through the center of the town, leading southeast 9 miles (14 km) to Bel Air, the county seat, and northwest 12 miles (19 km) to the Pennsylvania border north of Norrisville.

11.1% of all households were made up of individuals, and 5.4% had someone living alone who was 65 years of age or older.

None of the families and 1.4% of the population were living below the poverty line, including no under eighteens and 11.6% of those over 64.