William Osborn McDowell (1848–1927) was a financier and businessman. He founded numerous patriotic organizations in the late nineteenth century including the Sons of the American Revolution. With expanding international interests, he supported Cuban independence, helped found the League of Peace in 1908 and served as its president. He made his wealth from his investment firm, specializing in railroads, mining, and land speculation.
William Osborn McDowell was born on April 10, 1848 in Somerset, New Jersey. He was the son of Dr. Augustus William McDowell and Anna M. (Osborn) McDowell.
McDowell founded McDowell Brothers and Company in New York City, an investment firm specializing in silver mining, railroads, and land speculation. He reorganized the Montclair Railroad of New Jersey, the New York, Ontario and Western Railway of New Jersey, and the Midland Railroad of New Jersey, and consolidated many others. He was president of the San Antonio Silver Mining Company of Nevada, the Patent Company of Newark and New York, the Coal and Iron Exchange and the Greenwood Lake Improvement Company.
In the late nineteenth century, he became active in civic affairs. McDowell was a founding trustee in 1881 of the American Institute of Christian Philosophy, together with Cornelius Vanderbilt II and several learned ministers. It was intended to promote education in leading questions of religion and science.
He founded the Cuban American League of the U.S., which supported the fight for Cuban independence in the late nineteenth century. McDowell initiated the Pan Republic Congress, a business organization that worked for the standardization of international weights and measures, customs regulations, and the resolution of international disputes.
His interest in international affairs led him to become a leader in the universal peace movement of the late nineteenth and early twentieth centuries. He was among the founders of the Human Freedom League and the League of Peace. In 1908 McDowell drafted a Constitution of the United Nations of the World with political economists. The industrialist Andrew Carnegie was also among the founders, and President Theodore Roosevelt supported the League of Peace in a 1910 speech.