Horsham is a census-designated place (CDP) in Montgomery County, Pennsylvania, United States. The population was 14,842 at the 2010 census. Horsham is located entirely within Horsham Township, and it is home to the Horsham Air Guard Station at the former site of Naval Air Station Joint Reserve Base Willow Grove.
According to the United States Census Bureau, the CDP has a total area of 5.5 square miles (14 km2), all land.
The climate in this area is characterized by hot, humid summers and generally mild to cool winters. According to the Köppen Climate Classification system, Horsham has a humid subtropical climate, abbreviated "Cfa" on climate maps.
As of the 2010 census, the CDP was 84.4% Non-Hispanic White, 4.7% Black or African American, 0.2% Native American and Alaskan Native, 5.8% Asian, 0.1% Native Hawaiian and Other Pacific Islander, 1.2% were Some Other Race, and 1.6% were two or more races. 3.5% of the population were of Hispanic or Latino ancestry.
As of the census of 2000, there were 14,779 people, 5,798 households, and 3,907 families residing in the CDP. The population density was 2,704.6 people per square mile (1,045.1/km2). There were 5,917 housing units at an average density of 1,082.8/sq mi (418.4/km2). The racial makeup of the CDP was 90.10% White, 3.79% African American, 0.19% Native American, 4.34% Asian, 0.60% from other races, and 0.98% from two or more races. Hispanic or Latino of any race were 1.45% of the population.