General lvaro Obreg n Salido (February 19, 1880 – July 17, 1928) was President of Mexico from 1920 to 1924.

Born in the state of Sonora, he entered politics in 1911 with his election as mayor of the town of Huatabampo. At the time, he supported President Francisco Madero against a revolt led by Pascual Orozco. When Madero was overthrown and murdered in the revolt led by F lix D az and General Victoriano Huerta (and supported by US Ambassador Henry Lane Wilson), Obreg n joined Venustiano Carranza in revolt against Huerta's new government, and succeeded in forcing Huerta from power on July 14, 1914.

As a military commander, Obreg n was a strong supporter of Carranza when he took office, and helped him, as Minister of War and the Navy, to repel rebel forces loyal to Pancho Villa and Emiliano Zapata. The armies of Obreg n and Villa clashed in 4 battles. The first took place on April 6 and 7, 1915 that ended with the withdrawal of the 'villistas'. The second in Celaya took place between April 13 and 15, when Villa attacked the city of Celaya but was rejected. The third was the prolonged position battle of Trinidad and Santa Ana del Conde between April 29 and June 5, which was the definitive battle. Villa was again defeated by Obreg n, who lost his right arm in the fight. Villa made a last attempt to stop Obreg n's army in Aguascalientes on July 10, without success. All these battles are collectively known as the Celaya Battle the largest military confrontation in Latin American history before the Malvina's battles (Falkland's).

In the political sphere, he adopted a radical line, and pushed through various changes to the new constitution of 1917, including the rights of workers to organize, strike, earn a minimum wage, and work a maximum number of hours. Once it was enacted, he retired from politics to pursue farming.

Obreg n returned to politics in 1920, hoping to succeed Carranza as president. When it became apparent, however, that Carranza wanted to ensure that Ignacio Bonillas would succeed him, Obreg n organized the military in a successful revolt against the president. Carranza was killed in the state of Puebla in an ambush led by General Rodolfo Herrera as he fled from Mexico City to Veracruz on horseback. For six months, from June 1, 1920 to December 1, 1920, Adolfo de la Huerta served as provisional president of Mexico, until elections could be held. When Obreg n was declared the victor, de la Huerta stepped down and assumed the position of Secretary of the Treasury in the new government.

Obreg n's four years in office were known for the agrarian and anticlerical reforms he instituted and for the cultivation of good relations with the United States, based on the sale of Mexican petroleum to the American market. The greatest interruption to his term in office was a revolt by Adolfo de la Huerta, who regarded himself as the president's natural successor, while Obreg n preferred Plutarco El as Calles. Calles was elected and Obreg n stepped down from office.

In 1928, Obreg n ran again for office, winning a second term as president after a bitterly contested election. He returned to Mexico City to celebrate his victory, but was assassinated in a restaurant on July 17, 1928, by Jos de Leon Toral, a Roman Catholic seminary student opposed to Obreg n's anticlerical platform.

Ciudad Obreg n, in Gen. Obreg n's home state of Sonora, was renamed in his honor; so was lvaro Obreg n borough in Mexico City, which contains the site of his assassination.