|Incorporated||February 28, 1912|
|• Total||0.6 sq mi (2 km2)|
|• Density||170.6/sq mi (65.9/km2)|
|Time zone||EST (UTC-5)|
|• Summer (DST)||EDT (UTC-4)|
Addison is located at , about 30 miles (48 km) WNW of Cumberland, Maryland and about 30 miles (48 km) ENE of Morgantown, West Virginia. According to the United States Census Bureau, the borough has a total area of 0.6 square miles (1.6 km2), all land.(39.7472, -79.3331)
As of the census of 2000, there were 214 people, 87 households, and 54 families residing in the borough. The population density was 380.4 people per square mile (147.5/km²). There were 96 housing units at an average density of 170.6 per square mile (66.2/km²). The racial makeup of the borough was 100.00% White.
There were 87 households out of which 26.4% had children under the age of 18 living with them, 57.5% were married couples living together, 4.6% had a female householder with no husband present, and 36.8% were non-families. 34.5% of all households were made up of individuals and 20.7% had someone living alone who was 65 years of age or older. The average household size was 2.34 and the average family size was 3.04.
In the borough the population was spread out with 19.2% under the age of 18, 11.7% from 18 to 24, 27.1% from 25 to 44, 21.5% from 45 to 64, and 20.6% who were 65 years of age or older. The median age was 42 years. For every 100 females there were 96.3 males. For every 100 females age 18 and over, there were 90.1 males.
The median income for a household in the borough was $25,833, and the median income for a family was $34,250. Males had a median income of $28,750 versus $22,917 for females. The per capita income for the borough was $14,963. About 5.1% of families and 13.9% of the population were below the poverty line, including 6.1% of those under the age of eighteen and 25.4% of those sixty five or over.