It is served by the South Eastern School District which provides a public education.

[4] According to the U.S. Census Bureau, the borough has a total area of 0.3 square miles (0.78 km2), all land.

25.6% of all households were made up of individuals, and 10.9% had someone living alone who was 65 years of age or older.

Slate quarries opened in Delta in the 1840s, and quarrymen arrived from Wales.

[9] At the Crystal Palace Exposition of 1850, Peach Bottom slate was judged the finest in the world.

The Peach Bottom Railway entered Delta in 1876, and shipped slate along its line to Red Lion and York, Pennsylvania.

Its Welsh choir has won a prize at the highly competitive National Eisteddfod of Wales and performed at the wedding of Michael Douglas and Catherine Zeta Jones.