Donora is a borough in Washington County, Pennsylvania, United States, approximately 20 miles (32 km) south of Pittsburgh along the Monongahela River.

The borough's nickname is "The Home of Champions", mainly because of the large number of famous athletes who have called Donora their home, including Baseball Hall of Fame outfielders Stan Musial and Ken Griffey Jr. During the 1948 Donora smog, air pollution killed 20 people and caused respiratory problems for 6,000 of the 14,000 residents.

In 1794, the Whiskey Insurrectionists held several meetings at Fells Church, approximately 1 mile (1.6 km) east of Donora.

A trolley line opened in Donora on December 15, 1901, linking First and McKean, and Fifteenth Street and Meldon.

[7] Donora's neighborhood known as "Cement City" is listed on the National Register of Historic Places.

This structural building technique was championed by Thomas Edison, and was used by neighborhoods throughout the United States.

[9] Donora is home to the world's second largest "Cement City" housing tract, innovated by Thomas Edison.

The climate in this area is characterized by hot, humid summers and generally mild to cool winters.

Across the Monongahela River to the east, Donora runs adjacent with Rostraver Township in Westmoreland County.

Major companies that have facilities in the Donora Industrial Park include A-1 Babbit company, Apex N.A., Area Agency on Aging, Bergen Power Pipe Supports, BMA of Donora, HYTEC Inc., Dyno-Nobel Inc, Eastern Alloy, Eastern Hydraulic & Machine, Elizabeth Milling Corporation, Elliott Support Services, Glosser MFG, Industrial Nonferrous Casting Company, K-Z Tool Company, Airgas Specialty Products, Inc. (formerly LaRoche Industries), McGrew Welding Fabrication, Metalife Resources, MIDA Inc., Mon Valley Child Care, Mon Valley Sewage Authority, Monessen Ambulance Service, Nitrous Oxide Corporation, Power & Industrial Services Corporation, Nichols Miniatures, Pittsburgh Post Gazette Distribution Center, RAS Industries Inc., Regal Industries Inc.and Spartech Polycom.

For nearly three decades, John "Chummy" Lignelli was the mayor of the Borough of Donora, until he retired at age 93.