Castle Shannon City is located in Allegheny County, Pennsylvania. It is a part of the Pittsburgh Metropolitan Area. Castle Shannon is in the zip code 15234, and it borders Pittsburgh, Mount Lebanon, Bethel Park, and Whitehall, Pennsylvania. Its population is 8,371 people.
The city is bordered by five towns: Baldwin Township, the Pittsburgh neighborhood Overbrook, Whitehall, Bethel Park, and Mt. Lebanon. In 1877, the Castle Shannon railroad was built, linking the city to the West End neighborhood of Pittsburgh. The Pittsburgh Railroad purchased the right-of-way through the valley in 1909, and Castle Shannon became an important coal-mining district. The Pittsburgh and West Virginia Railroad followed suit shortly afterward.
The population of Castle Shannon is relatively small compared to other cities in the surrounding region. Sixty-seven percent of households are made up of married couples. This is below the average of other places in the region. The largest city with the highest percentage of married couples is Green Tree. The population of Castle Shannon is a bit below the national average, and is less than one-third of that of Bethel Park.
The percent of foreign-born residents in Castle Shannon is 7.3%, which is lower than the national average. The highest percent of foreign-born residents is in Whitehall, PA, which has a 12.6% percentage. While Castle Shannon, PA has a relatively low foreign-born population, it has a large percentage of Eastern Africans and Eastern Asians.