William Insco Buchanan (September 10, 1853 – October 17, 1909)[1] was an American diplomat who spent much of his career in Latin America.

[2] After receiving an education at the common schools in Ohio, he served as engrossing clerk of the Indiana House of Representatives from 1874 to 1875.

[3] On January 26, 1894, President Grover Cleveland (the former mayor of Buffalo and governor of New York) appointed Buchanan United States Minister to Argentina.

He ceased to act "on special mission," however, and conducted business in the capacity of Envoy Extraordinary and Minister Plenipotentiary until his departure.

[3] President McKinley was assassinated at the exposition by anarchist Leon Czolgosz on September 6, 1901, and Roosevelt traveled to Buffalo where he was inaugurated shortly thereafter.