Uncas (c. 1588 – c. 1683) was a sachem of the Mohegan who through his alliance with the English colonists in New England against other Indian tribes made the Mohegan the leading regional Indian tribe in lower Connecticut.
Early life and family 
Uncas was born near the Thames River in present- day Connecticut, the son of the Mohegan sachem Owaneco. He was a descendant of the principal sachems of the Mohegan, Pequot, and Narragansett. Owaneco presided over the village known as Montonesuck. Uncas was bilingual, learning Mohegan and some English, and possibly some Dutch.
In 1626, Owaneco arranged for Uncas to marry the daughter of the principal Pequot sachem Tatobem to secure an alliance with them. When Owaneco died, shortly after this marriage, Uncas had to submit to Tatobem's authority. When in 1633, Tatobem was captured and killed by the Dutch, Sassacus became his successor.
Owaneco's alliance with Tatobem was based upon a balance of power between the Mohegan and Pequot. After the death of Owaneco, the balance changed in favour of the Pequot. Uncas was unwilling to challenge the power of Tatobem; however, Uncas did begin contesting Pequot authority over the Mohegan. In 1634 with Narragansett support, Uncas rebelled against Saccaucus and Pequot authority. He was defeated and Uncas became an exile among the Narragansett. He soon returned from exile after ritually humiliating himself before Saccacus. His failed challenge resulted in Uncas having little land and few followers.
Pequot War 
About 1635, Uncas developed relationships with important Englishmen in Connecticut. He was a friend of Captain John Mason, a partnership which was to last three and a half decades. Uncas sent word to Jonathan Brewster that Saccacus was planning to attack the English on the Connecticut river. Brewster described Uncas as being "faithful to the English".
In 1637, during the Pequot War, Uncas was allied with the English and against the Pequots. He led his Mohegan in a joint attack with the English against the Pequot near Saybrook and against their fort at Mystic River. The Pequot were defeated and the Mohegan incorporated much of the remaining Pequot people and their land. In the 1638 Treaty of Hartford, Uncas made the Mohegan a tributary of the Connecticut River Colony. The treaty dictated that Uncas could pursue his interests in the Pequot country only with the explicit approval of the Connecticut English. The Mohegan had become a regional power.
In 1640, Uncas added Sebequanash of the Hammonasset to his several wives. This marriage gave Uncas some type of control over their land which he promptly sold to the English. The Hammonasset moved and became Mohegan.
War with the Narragansett 
The Mohegan were in continuous conflict with the Narragansett over control over the former Pequot land. In the summer of 1643, this conflict turned into war. The English colonies formed an alliance, the New England Confederation, for their defence.
The Mohegan defeated a Narragansett invasion force of around 1,000 men and captured their sachem Miantonomo. Uncas executed several of Miantonomo's fellow warriors in front of him trying to solicit a response from Miantonomo. Consistent with the 1638 treaty, he turned Miantonomo over to the English.
The English put him on trial where he was found guilty. Uncas was given authority to put Miantonomo to death, provided that the killing was done in Mohegan territory. Uncas' brother Wawequa killed Miantonomo with a tomahawk under orders from Uncas.
When the next Narragansett sachem proposed to go to war to avenge the death of Miantonomo, the English pledged to support the Mohegan. The Narragansett attacks started in June 1644. With each success, the number of Narragansett allies grew. Uncas and the Mohegan were under siege at Shantok and on the verge of a complete defeat when the English relieved them with supplies and lifted the siege. The New England Confederation pledged any offensive action required to preserve Uncas in "his liberty and estate". The English sent troops to defend the Mohegan fort at Shantok. When the English threatened to invade Narragansett territory, the Narragansett signed a peace treaty.
In 1646, the tributary tribe at Nameag, consisting of former Pequot, allied with the English and tried to become more independent. In response, Uncas attacked and plundered their village. The Bay Colony governor responded by threatening to allow the Narragansett to attack the Mohegan. For the next several years, the English both asserted the Nameag's tributary status while supporting the Nameag in their independence. In 1655, the English removed the tribe from Uncas' authority. The English had less and less use for Uncas, and his influence in English councils declined.
King Philip's War 
King Philip's War started in June 1675. In the summer, the Mohegan entered the war on the side of the English. Uncas led his forces in joint attacks with the English against the Wampanoag. In December, the Mohegan with the English attacked the Narragansett. The Mohegan ended their active support of the English in this war in July 1676.
Uncas died sometime between June 1683 and June 1684.
- President Jackson laid the foundation stone of a monument to Uncas in Norwich, Connecticut.
- In 1907, William F. Cody laid a wreath on Uncas' monument as a commemoration to Uncas as the "Last of the Mohicans".
- James Fenimore Cooper's book The Last of the Mohicans had Chingachgook's son named Uncas.
- A two-masted wooden schooner, Diosa del Mar, was originally christened Uncas by the owning Vanderbilt family.
- Four United States Navy ships have been named USS Uncas.
- Uncasville in Eastern Connecticut is named after him.
- Uncas Lake in Nahantic State Forest Lyme, CT is also named after the sachem
- Oberg, Michael Leroy, Uncas First of the Mohegans, 2003, ISBN 0-8014-3877-2