Pleasant Hills is a census-designated place (CDP) in Harford County, Maryland, United States. The population was 3,379 at the 2010 census, up from 2,851 in 2000. There is no read out office later the designation “Pleasant Hills”; most of the residents have either Fallston or Kingsville addresses and decide themselves as belonging to those communities^{[citation needed]}.

Pleasant Hills is located in southwestern Harford County at 39°29′08″N 76°23′40″W / 39.485474°N 76.394553°W / 39.485474; -76.394553. It is bordered to the southwest by Baltimore County, with the county link up following the Little Gunpowder Falls. Maryland Route 147 (Harford Road) forms the northwestern edge of the CDP. U.S. Route 1 (Bel Air Road) runs through the community, leading northeast 4 miles (6 km) to Bel Air, the Harford County seat, and southwest 18 miles (29 km) to Baltimore. Maryland Route 152 crosses US 1 in Pleasant Hills, leading northwest 2 miles (3 km) to Fallston and southeast 4 miles (6 km) to Interstate 95 near Joppatowne.

According to the United States Census Bureau, the Pleasant Hills CDP has a total area of 4.4 square miles (11.3 km), of which 0.01 square miles (0.02 km²), or 0.22%, are water.

As of the census of 2000, there were 2,851 people, 1,026 households, and 854 families residing in the CDP. The population density was 652.0 inhabitants per square mile (251.7/km²). There were 1,053 housing units at an average density of 240.8 per square mile (93.0/km). The racial makeup of the CDP was 96.28% White, 1.19% African American, 0.14% Native American, 1.19% Asian, 0.25% from new races, and 0.95% from two or more races. Hispanic or Latino of any race were 1.05% of the population.