According to the United States Census Bureau, the city has a total area of 1.1 square miles (3.0 km²), of which, 0.8 square miles (2.1 km²) of it is land and 0.3 square miles (0.9 km²) of it (30.43%) is water.
There were 697 households out of which 24.1% had children under the age of 18 living with them, 56.7% were married couples living together, 9.0% had a female householder with no husband present, and 32.6% were non-families. 30.4% of all households were made up of individuals and 18.7% had someone living alone who was 65 years of age or older. The average household size was 2.23 and the average family size was 2.75.
In the city the population was spread out with 19.3% under the age of 18, 5.9% from 18 to 24, 23.0% from 25 to 44, 28.1% from 45 to 64, and 23.7% who were 65 years of age or older. The median age was 46 years. For every 100 females there were 87.7 males. For every 100 females age 18 and over, there were 83.6 males.
The median income for a household in the city was $40,000, and the median income for a family was $49,306. Males had a median income of $40,352 versus $25,588 for females. The per capita income for the city was $24,409. About 5.4% of families and 6.5% of the population were below the poverty line, including 6.9% of those under age 18 and 9.6% of those age 65 or over.
Glen Dale is the hometown of country music star Brad Paisley, Congresswoman Shelley Moore Capito, and her father, former Governor Arch A. Moore, Jr. Baseball Hall of Famer George Brett was born in Glen Dale, but his family moved when he was a small child, and he was primarily raised in Southern California.