The Iroquois League, the most powerful Native American confederacy at the time, was initially divided in its loyalties due to internal disputes and differing opinions among its member nations. However, by 1779, most of the Iroquois had sided with the British, primarily because they feared that an American victory would lead to further encroachment on their lands.
Other tribes that supported the British included the Cherokee, the Shawnee, and the Delaware. These tribes were motivated by similar concerns about land rights, as well as a desire to maintain their traditional way of life.
The Americans were also able to secure the support of some Native American tribes, including the Oneida and the Tuscarora nations of the Iroquois League, as well as the Catawba and the Wampanoag tribes. These tribes were motivated by a variety of factors, including gratitude for past assistance from the Americans, a desire to protect their lands from British encroachment, and a belief that the American cause was just.
Overall, the majority of Native American tribes remained neutral during the Revolutionary War, but those that did take sides were roughly evenly divided between the British and the Americans.