|Elevation||397 ft (121.0 m)|
|Area||1.6 sq mi (4.1 km2)|
|- land||1.6 sq mi (4 km2)|
|- water||0.0 sq mi (0 km2)|
|Density||1,780.2/sq mi (687.3/km2)|
|- summer (DST)||EDT (UTC-4)|
|Area code||610 and 484|
Reiffton is located at (40.315642, -75.872337).
According to the United States Census Bureau, the CDP has a total area of 1.6 square miles (4.1 km2), all of it land.
As of the census of 2000, there were 2,888 people, 1,079 households, and 854 families residing in the CDP. The population density was 1,780.2 people per square mile (688.3/km²). There were 1,099 housing units at an average density of 677.5/sq mi (261.9/km²). The racial makeup of the CDP was 97.13% White, 1.11% African American, 0.03% Native American, 1.11% Asian, 0.21% from other races, and 0.42% from two or more races. Hispanic or Latino of any race were 0.97% of the population.
There were 1,079 households, out of which 30.0% had children under the age of 18 living with them, 69.3% were married couples living together, 7.1% had a female householder with no husband present, and 20.8% were non-families. 18.0% of all households were made up of individuals, and 9.9% had someone living alone who was 65 years of age or older. The average household size was 2.56 and the average family size was 2.89.
In the CDP the population was spread out, with 22.1% under the age of 18, 4.3% from 18 to 24, 22.7% from 25 to 44, 27.8% from 45 to 64, and 23.1% who were 65 years of age or older. The median age was 46 years. For every 100 females there were 91.8 males. For every 100 females age 18 and over, there were 88.1 males.
The median income for a household in the CDP was $60,893, and the median income for a family was $68,444. Males had a median income of $50,833 versus $36,970 for females. The per capita income for the CDP was $25,866. About 1.0% of families and 1.4% of the population were below the poverty line, including none of those under age 18 and 5.7% of those age 65 or over.