Donora is a borough in Washington County, Pennsylvania, USA, 20 miles (32 km) south of Pittsburgh on the Monongahela river. Donora was incorporated in 1901. Donora got its name from a combination of William Donner and Nora Mellon, banker Andrew Mellon's wife. Agriculture, coal-mining, steel-making, wire-making, and other industries were conducted in Donora early in its history. In 1910, 8,174 people lived there; in 1920, 14,131; and in 1940, 13,180 people lived in Donora. The population was 5,653 at the 2000 census. Donora is a Rust Belt place which has lost most of its industrial capacity. It is in the "Mon valley" five miles (8 km) downriver from Charleroi and 25 miles (40 km) upstream of Braddock.
Between October 26 and October 31 1948 an air inversion trapped industrial effluent (air pollution) from the American Steel and Wire plant and Donora Zinc Works. "In three days, 18 people died... After the inversion lifted, another 50 died. Hundreds more finished the rest of their lives with damaged lungs and hearts. But another 40 years would pass before the whole truth about Donora's bad air made public-health history."
Donora is the birthplace of baseball stars Stan Musial, Ken Griffey, Sr., and Ken Griffey, Jr.
According to the United States Census Bureau, the borough has a total area of 2.0 square miles (5.3 km²), of which, 1.9 square miles (4.9 km²) of it is land and 0.2 square miles (0.4 km²) of it (7.32%) is water.
There were 2,469 households out of which 23.4% had children under the age of 18 living with them, 36.9% were married couples living together, 16.5% had a female householder with no husband present, and 41.9% were non-families. 37.4% of all households were made up of individuals and 21.3% 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 2.95.
In the borough the population was spread out with 21.7% under the age of 18, 6.4% from 18 to 24, 25.5% from 25 to 44, 21.4% from 45 to 64, and 25.0% who were 65 years of age or older. The median age was 42 years. For every 100 females there were 82.7 males. For every 100 females age 18 and over, there were 78.4 males.
The median income for a household in the borough was $27,939, and the median income for a family was $37,176. Males had a median income of $33,725 versus $22,346 for females. The per capita income for the borough was $17,893. About 12.4% of families and 16.8% of the population were below the poverty line, including 28.2% of those under age 18 and 14.0% of those age 65 or over.