Clarendon is a borough in Warren County, Pennsylvania, United States. The population was 564 at the 2000 census.Clarendon is located at 41°46′52″N 79°5′42″W / 41.78111°N 79.09500°W / 41.78111; -79.09500.According to the United States Census Bureau, the borough has a total area of 0.4 square miles, all of it land.As of the census of 2000, there were 564 people, 220 households, and 150 families residing in the borough. The population density was 1,308.6 people per square mile. There were 239 housing units at an average density of 554.5 per square mile. The racial makeup of the borough was 97.52% White, 0.18% Native American, 1.06% Asian, and 1.24% from two or more races. Hispanic or Latino of any race were 1.06% of the population.There were 220 households out of which 32.7% had children under the age of 18 living with them, 55.9% were married couples living together, 8.6% had a female householder with no husband present, and 31.8% were non-families. 26.