Joseph LaFlesche, also known as E-sta-mah-za or Iron Eye (1822–1888), was the last recognized head chief of the Omaha tribe of Native Americans who was selected according to the traditional tribal rituals. The head chief Big Elk had adopted LaFlesche as an adult into the Omaha and designated him in 1843 as his successor. LaFlesche was of Ponca and French Canadian ancestry; he became a chief in 1853, after Big Elk's death. An 1889 account contends that he had been the only chief of any European ancestry among the Omaha.
In 1854 LaFlesche was among the seven Omaha chiefs in the delegation who went to Washington, DC for final negotiations and signed the treaty with the United States by which they ceded most of the Omaha territory. About 1856, he led his people in relocating to the Omaha reservation in what is now northeastern Nebraska. LaFlesche served as principal chief until 1888. He led during the Omaha transition to the reservation and other major social changes.
Joseph LaFlesche, also called E-sta-mah-za (Iron Eye), was the son of Joseph LaFlesche, a French-Canadian fur trader, and Waoowinchtcha, his Ponca wife. (An 1889 account said she was related to Big Elk, chief of the Omaha.)
The younger LaFlesche accompanied his father from the age of 10 on trading trips. His father worked for the American Fur Company (AFC) with the many tribes: Ponca, Omaha, Iowa, Otoe, and Pawnee, living between the Platte and Nebraska rivers. They spoke closely related Siouan languages. The father and son learned the Omaha-Ponca language from Waoowinnchtcha, and the Omaha people.
The younger Joseph La Flesche started working for the American Fur Company at about the age of 16 and worked for them until 1848. By then he had settled with his family and the Omaha at the Bellevue Agency. He had been adopted into the Omaha tribe as the son of Big Elk, the principal chief, after years of interaction with the people. In 1843 Big Elk had designated La Flesche as his successor, and the younger man began to study tribal ways and customs, becoming prepared to be chief. He joined the tribal council about 1849.