On November 2, 1783 following the close of the American Revolutionary War, US General George Washington gave his "Farewell Address to the Army" in Rocky Hill.
Rocky Hill is located at 40°24'1" North, 74°38'20" West (40.400406, -74.638955)1.
According to the United States Census Bureau, the borough has a total area of 1.7 km² (0.7 mi²). 1.7 km² (0.7 mi²) of it is land and none of the area is covered with water.
As of the census of 2000, there are 662 people, 284 households, and 189 families residing in the borough. The population density is 381.5/km² (982.0/mi²). There are 295 housing units at an average density of 170.0/km² (437.6/mi²). The racial makeup of the borough is 95.17% White, 1.36% African American, 0.00% Native American, 0.45% Asian, 0.60% Pacific Islander, 0.91% from other races, and 1.51% from two or more races. 3.93% of the population are Hispanic or Latino of any race.
There are 284 households out of which 24.3% have children under the age of 18 living with them, 60.9% are married couples living together, 4.9% have a female householder with no husband present, and 33.1% are non-families. 27.8% of all households are made up of individuals and 12.7% have someone living alone who is 65 years of age or older. The average household size is 2.33 and the average family size is 2.82.
In the borough the population is spread out with 20.2% under the age of 18, 3.3% from 18 to 24, 28.1% from 25 to 44, 31.1% from 45 to 64, and 17.2% who are 65 years of age or older. The median age is 44 years. For every 100 females there are 98.2 males. For every 100 females age 18 and over, there are 95.6 males.
The median income for a household in the borough is $79,469, and the median income for a family is $100,314. Males have a median income of $54,375 versus $50,357 for females. The per capita income for the borough is $48,357. 2.7% of the population and 2.5% of families are below the poverty line. Out of the total people living in poverty, 1.8% are under the age of 18 and 5.3% are 65 or older.