Alexandria is a borough in Huntingdon County, Pennsylvania, United States. The population was 401 at the 2000 census.
According to the United States Census Bureau, the borough has a total area of 0.1 square miles (0.3 km2), all of it land.
As of the census of 2000, there were 401 people, 149 households, and 106 families residing in the borough. The population density was 3,503.4 people per square mile (1,407.5/km²). There were 160 housing units at an average density of 1,397.9 per square mile (561.6/km²). The racial makeup of the borough was 96.76% White, 1.50% Asian, 1.00% Pacific Islander, 0.75% from other races. Hispanic or Latino of any race were 2.00% of the population.