Dorneyville is located in south-central Lehigh County in the southern corner of South Whitehall Township and the west end of Salisbury Township. It is bordered to the northeast and east by the Allentown city limits, and to the northwest by the unincorporated community of Cetronia.

I-78 forms the southern boundary of Dorneyville, with access from Exit 54 (U.S. 222/Hamilton Boulevard) and Exit 55 (South Cedar Crest Boulevard). I-78 leads west 80 miles (130 km) to Harrisburg, the state capital, and east 90 miles (140 km) to the Holland Tunnel and Lower Manhattan. US 222 leads southwest 34 miles (55 km) to Reading. South Cedar Crest Boulevard leads south as Pennsylvania Route 29, 3 miles (5 km) to Emmaus.

According to the U.S. Census Bureau, Dorneyville has a total area of 2.0 square miles (5.2 km²), of which 0.01 square miles (0.02 km²), or 0.46%, are water.^[5] Cedar Creek, a northeast-flowing tributary of Little Lehigh Creek, runs through the northwest side of the Dorneyville, where Dorney Park is located. Dorneyville, through the Little Lehigh River, is part of the Lehigh River and Delaware River watersheds.

As of the 2010 census,^[7] there were 4,406 people and 1,705 total housing units. The 2013-2017 American Community Survey 5-Year Estimates^[8] determined that the current population of Dorneyville is approximately 4,262. About 46.9% is male and 53.1% is female. The median age is 48.2. The racial makeup is about 85.6% White, 9.5% African American, 3.0% Asian, 0.6% Hispanic or Latino 0.5% of some other race, and 1.3% of two or more races. 96.2% of people have graduated high school. The median household income is $88,968. Only 2.2% of civilians lie below the poverty line.