Ciudad Obregón is a city in southern Sonora. It is the state's second largest city after Hermosillo and serves as the municipal seat of Cajeme, as of 2020, the city has a population of 436,484. Ciudad Obregón is south of the state's northern border. History The city, previously named Cajeme, takes its name from Mexican Revolutionary Álvaro Obregón, a native of nearby Huatabampo, Sonora. Álvaro Obregón became president of Mexico after the Revolution and initiated an "agricultural revolution" in the Yaqui Valley, introducing modern agricultural techniques and making this valley one of the most prosperous agricultural regions in the country. Renowned US agronomist Dr. Norman Borlaug, the architect of the "Green Revolution" worked here after successful developments in increasing the resistance of wheat. For his efforts he was later awarded the Nobel Prize. The origins of this city date back to the year 1906 when the company's rail track South Pacific Railway reached this area of the Yaqui Valley; this route, made it possible to incorporate with the Mayo Valley to the domestic and external market, attracting a wave of investors and settlers who brought out populations. In 1907, a flag station was established for the locomotive crossing the state to supply water, this station was called Cajeme. Cajemé was a Yaqui leader (whose population lives in this area) who fought against them as part of the Porfyrian army; and then led the Yaqui rebellion against it Porfirio Díaz. "The Cajeme station was run by the American Bert Cameron, superintendent, and Emilio Estrella, station manager. They and their families were the first settlers. Soon after, the cowboys arrived to guard the corrals of cattle that from here was sent to other regions. Soon came neighbors of Hope, near the fields cultivated in the Valley." The Yaquis offered resistance to the arrival of the first settlers on their lands. The first neighborhood was called Plano Oriente. In 1923, 'Cajeme Motors' was installed, owned by American James Huffaker, it was the first auto agency; fact that contributed significantly to the development of Cajeme. At the end of his term as president of the country (1920–1924), the General Alvaro Obregón returned to Sonora and carried out business projects in Navojoa and Cajeme, creating in 1925, the company 'Obregón y Cía.', which provided more work and economic development in the Region. On 29 November 1927, Cajeme was declared the head of the municipality (until