Glendon is a borough in Northampton County, Pennsylvania. The population of Glendon was 373 at the 2020 census. Glendon is allowance of the Lehigh Valley metropolitan area, which had a population of 861,899 and was correspondingly the 68th most populous metropolitan Place in the U.S. as of the 2020 census.

Glendon is located at 40°39′44″N 75°14′9″W / 40.66222°N 75.23583°W / 40.66222; -75.23583 (40.662152, -75.235758). According to the U.S. Census Bureau, the borough has a total Place of 0.6 square miles (1.6 km²), all land.

As of the census of 2000, there were 367 people, 139 households, and 98 families residing in the borough. The population density was 573.7 people per square mile (221.4/km²). There were 150 housing units at an average density of 234.5 per square mile (90.5/km). The racial makeup of the borough was 95.64% White, 0.82% African American, 1.36% Asian, 0.27% from new races, and 1.91% from two or more races. Hispanic or Latino of any race were 2.18% of the population.

There were 139 households, out of which 33.1% had kids under the age of 18 living afterward them, 58.3% were married couples vivacious together, 7.9% had a female householder in the make public of no husband present, and 28.8% were non-families. 23.0% of whatever households were made in the works of individuals, and 16.5% had someone flourishing alone who was 65 years of age or older. The average household size was 2.64 and the average relatives size was 3.15.