The William H. Donner Foundation is a family foundation controlled by 29 descendants of William Henry Donner (1864-1953). Although best known for its grants to center-right advocacy organizations, it appears to have reduced this grantmaking in the past decade to increase grants for animal protection and environmentalist causes.
Donner Foundation founder William Donner made his fortune in the steel business, creating, in collaboration with Andrew W. Mellon, a steel mill in Donora, Pennsylvania. The company Donner and Mellon created was bought by U.S. Steel. Donner subsequently moved to Canada and lived in Montreal for the last quarter century of his life. Shortly before his death, he created the Donner Canadian Foundation to support Canadian programs. 
The Donner Foundation was formed in 1932 as the International Cancer Research Foundation after a son died of lung cancer.  The name was changed after Donner’s death. The foundation was originally based in Philadelphia, but in 1960 the foundation split into the Independence Foundation, which funds Philadelphia-based programs, and the more nationally-focused Donner Foundation. 
From 1990, the Donner Foundation supported a wide range of center-right organizations and causes. In 1993 the foundation, collaborating with the Sarah Scaife and Earhart Foundations, supported a study by media researchers Robert Lichter, Stanley Rothman, and Mark Mills that argued the media exaggerated the risks of getting cancer from food additives, pollution, and nuclear power.  In the late 1990s, the foundation funded the reporting in Reason magazine of Michael Fumento, a journalist skeptical of many claims made by environmentalists.  In 1998, the Donner Foundation gave the James Madison Institute, a Florida free-market think tank, $250,000 to start charter schools in that state. 
The Donner Foundation also supports nonprofits created by Princeton political scientist Robert George. In 2006, George told The Nation that Donner, along with the Olin and Bradley Foundations and “several dedicated individual donors” provided “much needed funding” for the Madison Program, a center affiliated with the university that supports fellows and funds scholarly research. In 2014, the Daily Princetonian identified Donner, along with DonorsTrust and the Bradley Foundation, as a supporter of the Witherspoon Institute, a nonprofit created by George that provides educational programs for high school and college students. 
In 2017, the Donner Foundation provided grants of between $10,000 and $50,000 to many center-right organizations, including Americans for Tax Reform Foundation, Competitive Enterprise Institute, Foundation for Economic Education, Hudson Institute, and Manhattan Institute for Policy Research. The foundation also gave to several left-wing and environmentalist groups, including the Drug Policy Alliance, the Institute for Policy Studies, and the Rainforest Action Network for a program “addressing labor exploitation on the palm oil industry.” 
While the Donner Foundation did not give any six-figure grants to any center-right organization, it donated $103,000 to the Nature Conservancy in 2017 and $150,000 to Amazon Watch. Its largest single grant in 2017 was $200,000 to the Carter Center for a program to reduce blindness in Ethiopia.