Its total land area is 307.03 sq mi (795.2 km2)[3] and the reservation population, including non-Native residents, was 4,526 in the 2020 census.

[citation needed] The Omaha people migrated to the upper Missouri area and the Plains by the late 17th century from earlier locations in the Ohio River Valley.

They were also related to the Siouan-speaking Osage, Quapaw, and Kansa peoples, who also migrated west under pressure from the Iroquois in the Ohio Valley.

In 1718, the French cartographer Guillaume Delisle mapped the tribe as "The Maha, a wandering nation", along the northern stretch of the Missouri River.

Around 1734 the Omaha established their first village west of the Missouri River on Bow Creek in present-day Cedar County, Nebraska.

[8] Around 1800, a smallpox epidemic, resulting from contact with Europeans, swept the area, reducing the tribe's population dramatically by killing approximately one-third of its members.

Aware they traditionally lacked a large population as defense from neighboring tribes, Blackbird believed that fostering good relations with white explorers and trading were the keys to their survival.

[8] After the United States made the Louisiana Purchase and exerted pressure on the trading in this area, there was a proliferation of different kinds of goods among the Omaha: tools and clothing became prevalent, such as scissors, axes, top hats and buttons.

They created sod houses for winter dwellings, which were arranged in a large circle in the order of the five clans or gentes of each moitie, to keep the balance between the Sky and Earth parts of the tribe.

By the Fourth Treaty of Prairie du Chien in 1831, the Omaha ceded their lands in Iowa to the United States, east of the Missouri River, with the understanding that they still had hunting rights there.

European-American settlers pressed the US government to make more land available west of the Mississippi River for white development.

In 1846 Big Elk made an illegal treaty allowing a large group of Mormons to settle on Omaha land for a period; he hoped to gain some protection from competing natives by their guns, but the new settlers cut deeply into the game and wood resources of the area during the two years they were there.

[9] For nearly 15 years in the 19th century, Logan Fontenelle was the interpreter at the Bellevue Agency, serving different US Indian agents.

In January 1854 he acted as interpreter during the agent James M. Gatewood's negotiations for land cessions with 60 Omaha leaders and elders, who sat in council at Bellevue.

The Omaha elders refused to delegate the negotiations to their gens chiefs, but came to an agreement to sell most of their remaining lands west of the Missouri to the United States.

Competing interests may be shown by the draft treaty containing provisions for payment of tribal debts to the traders Fontenelle, Peter Sarpy, and Louis Saunsouci.

[10] The chiefs at council agreed to move from the Bellevue Agency further north, finally choosing the Blackbird Hills, essentially the current reservation in Thurston County, Nebraska.

[11] Although the draft treaty authorized the seven chiefs to make only "slight alterations," the government officials forced major changes when they met.

By the 1870s, bison were quickly disappearing from the plains, and the Omaha had to rely increasingly for survival upon their cash annuities and supplies from the United States Government and adaptation to subsistence agriculture.

Jacob Vore was a Quaker appointed as US Indian agent to the Omaha Reservation under President Ulysses S. Grant.

Instead, he supplied goods: harrows, wagons, harnesses and various kinds of plows and implements to support the agricultural work.

Beginning in the 1960s, the Omaha began to reclaim lands east of the Missouri River, in an area called Blackbird Bend.

After lengthy court battles and several standoffs, much of the area has been recognized as part Omaha tribal lands.

Before having ceremonial reburial of the remains on Omaha lands, the tribe's representatives arranged for research at the University of Nebraska to see what could be learned from their ancestors.

[5] In pre-settlement times, the Omaha had an intricately developed social structure that was closely tied to the people's concept of an inseparable union between sky (male principle) and earth (female); it was part of their creation story and their view of the cosmos.

Each gens had a hereditary chief, through the male lines, as the tribe had a patrilineal kinship system of descent and inheritance.

[16] In 1888 Francis La Flesche, a young Omaha anthropologist, helped arrange for his colleague Alice Fletcher to have the Sacred Pole taken to the Peabody Museum of Archaeology and Ethnology at Harvard University, for preservation of it and its stories, at a time when the tribe's continuity seemed threatened by pressure for assimilation.

[17] La Flesche and Fletcher gathered and preserved stories about the Sacred Pole by its last keeper, Yellow Smoke, a holy man of the Hong'a gens.

When the museum returned the Sacred Pole to the tribe in July 1989, the Omaha held an August pow-wow in celebration and as part of their revival.