The Caddo Confederacy, or Caddo Nation, is a confederacy of several Southeastern Native American tribes, who traditionally inhabited much of what is now East Texas, northern Louisiana and portions of southern Arkansas and Oklahoma. Today the Caddo Nation of Oklahoma is a single federally recognized tribe with its capital at Binger, Oklahoma. The different Caddo languages have converged into two Caddo language dialects which are mutually understandable.

European chroniclers referred to the Caddo groups as the Hasinai, Kadohadacho, and Natchitoches confederacies, although the "confederacies" are better interpreted as kin-based affiliated groups or bands of Caddo communities. The Haisinai lived in the Neches and Angelina River valleys in  East Texas, the Kadohadacho lived on the Red River in the Great Bend area near the border of Texas, Oklahoma, and Arkansas, and the Natchitoches lived in what is now northern Louisiana on the Red River in the vicinity of the French post of Natchitoches (Fort St. Jean Baptiste aux Natchitos), which was established in 1714. The Hasinai, Kadohadacho, and Natchitoches were loosely affiliated with other tribes.

The Haisinai confederacy included:

• Hainai
• Nabedache
• Nabiti
• Nacogdoche
• Nacono
• Nadaco
• Nasoni (Lower)
• Nechaui
• Neche

The  Kadohadacho confederacy included:

• Kadohadacho
• Nanatsoho
• Nasoni (Upper)
• Natchitoches (Upper)

The Natchitoches confederacy included:

• Doustioni
• Natchitoches (Lower)

Other affiliated tribes:

• Adai
• Cahinnio
• Eyeish
• Ouachita
• Tula
• Yatasi

The roots of these peoples can be traced to Fourche Maline or Woodland Period culture groups that began to settle down in small communities, to manufacture ceramics for cooking and storage of foodstuffs, and to develop a horticultural way of life based on the raising of tropical cultigens (corn, squash, and later beans) and certain native plants.

The development of prehistoric Caddo culture may have been the result of several factors, including:

• (a) the rise, elaboration, and maintenance of complex social and political symbols of authority, ritual, and ceremony (centering on the construction, dismantling, remodeling, and use of earthen temple and burial mounds);

• (b) the development of elite status positions within certain Caddo communities;

• (c) increased sedentary life; and

• (d) the expanding reliance on tropical cultigens in the economy, with an intensification in the use of maize agriculture after about A.D. 1200.

Regardless of the processes involved, it is clear that after about A.D. 900, the Caddo groups were complex and socially ranked societies with well-planned civic-ceremonial centers, conducted elaborate mortuary rituals and ceremonial practices, and engaged in extensive interregional trade. Caddoan societies shared much with their Mississippian neighbors, particularly the adoption of maize and the development of maize agricultural economies, as well as systems of social authority and ceremony.

Delisle's map of 1703 places a series of related Caddo groups along a considerable stretch of a western tributary of the Mississippi River, obviously the Red River. Beginning on the lower Red River with the Nachitoches [Natchitoches] and proceeding up river, other Caddo groups included the Nakasa (one of the enemies of the Kadohadacho in 1687, according to Joutel), Yatache [Yatasi], Natsoos [Nanatsoho], Cadodaquiro [Cadohadacho], the [upper] Nachitoches, and the Nassonis [upper Nasoni]. Upstream from them on the Red River were the Canouaouana and Chaquanhe tribes, apparently enemies of the Cadohadacho, again according to Joutel.

The westernmost Caddo groups were shown by Delisle (1703) living on and near the Rio aux Cenis (probably the Neches River), Cenis (or Senys) being the French name for the Hasinai Caddo. Other than the mistake of having the Rio aux Cenis running into the Red River, Delisle's map shows that the French had a good understanding of the locations of the various Hasinai Caddo groups, from the Inahe [Hainai] to the east (on the Angelina river), the Nadaco and Nassonis [lower Nasoni] to the north and west, and a series of Cenis (Hasinai) communities along the western boundaries of their territory.

No Caddo communities are depicted west of the Trinity River (Rio Baho), with the closest non-Caddo communities living between the Trinity and Brazos (La Maligne R.) rivers. On the Brazos River lived the Canohatino tribe, one of the enemies of the Hasinai Caddo. That tribe felt the brunt of a French-Caddo attack in 1687 where more than 40 Canohatino were massacred by the joint armed forces.

By the 1750s, the Europeans (especially the French) possessed a much better perception of the location of the Hasinai Caddo groups and related Caddo tribes in east Texas and western Louisiana. This is not surprising considering that, reportedly, there was a French trader living at each of the major Caddo settlements, even those in the province of Texas (which was claimed by Spain). In a 1757 French map, Caddo groups are dispersed from east of the Sabine River (Rio Zavinas), near the Spanish presidio at Los Adaes, to just west of the Neches River (Rio de Nechas), with Spanish missions in their midst at Nacoudoches [Mission Nuestra Senora de los Nacogdoches] and de los Hays [Mission Nuestra Senora Dolores de Ais].

Between the 1750s and the 1780s, the Tawakoni, Yscani, and Kichai tribes, affiliated Wichita-speaking tribes, had moved south (from Kansas and Oklahoma) and settled in large villages along the margins of the Post Oak Savanna, in traditional Caddo hunting territory. The Hasinai Caddo tribes and the Wichita groups became strong allies, and the Caddo leaders were of great assistance in concluding formal and peaceful relations between the Wichita-speaking tribes and the Spanish in 1771-1772, and again between the Caddo, the Wichita-speaking tribes, and the Republic of Texas in 1843. The Bidai tribe, also allies to the Hasinai, lived to their south along the Trinity and Neches-Angelina rivers.

Because of the outbreak of epidemics at the Spanish settlement of Nacogdoches in the late 1770s to early 1780s, the Nadaco Caddo moved north along the Caddo Trace (a major trade path/road probably in existence for hundreds of years) to resettle on the Sabine River, where they remained until the establishment of the Republic of Texas. The Cadohadacho groups, with populations also diminished by epidemics, by this time had coalesced into one village for protection against the Osage, and relocated by 1795 along a small tributary feeding into Caddo Lake, a natural lake formed by the Great Raft along the Red River valley.

Most of the Cadohadacho remained in the Caddo Lake area until 1842, while others had moved into Indian Territory (Oklahoma) shortly after 1836, or had settled in the upper Trinity River drainage.

The Hasinai Caddo groups — the Nacogdoche, the Hasinai, and Nabedache—remained in their east Texas homelands, living in the early 1800s outside of the Spanish settlement of Nacogdoches, west to the Neches River, and north of the El Camino Real. Anglo settlement had pushed immigrant Indians from the Southeastern U.S., including the Biloxi, Alabama, Coushatta, Choctaw, and Cherokee, into the Caddo Homeland. These groups began to settle within traditional Caddo territory, both north and south of Nacogdoches, as well as along the Red River north and east of Caddo Lake.

The Alabama and Coushatta people asked for, and received, the permission of the Cadohadacho caddi to resettle along the Red River, and they became strong allies of the Caddo peoples. This was not the case with the Choctaw, as conflicts began between them and the Hasinai Caddo groups over hunting territories almost immediately after the Choctaw moved into East Texas. Later, however, the Choctaw allied with the Caddo peoples and the Cherokee in war parties against the Osage.

Between about 1836 and 1842, the Hasinai, Nadaco, and Cadohadacho tribes had all been forcibly pushed out of East Texas, some moving into Indian Territory, while others moved west into the upper Brazos River drainage. This was the final and bitter end to the Caddo settlement of their traditional homelands.

Though the Caddo groups made a successful agricultural living for a few short years in the hard but seemingly fertile lands of the Brazos River valley, they were never secure from Anglo-American encroachments, even when settled on the Brazos Reserve in 1855. They were compelled in 1859, according to John R. Swanton, noted ethnologist at the Smithsonian Institution, "to abandon their homes, the fruit of their labors, and the graves of their kindred," and were removed to the Washita River valley in Indian Territory.