Lewis Henry Morgan (November 21, 1818 – December 17, 1881) is considered to be the "Father of American Anthropology," although his professional life was in the field of law. He graduated from Union College in 1840 and returned to his birth city of Aurora, New York to read law, which he practiced in Aurora and Rochester. Morgan served in the New York State Assembly and Senate.

Morgan became interested in the Native Americans of his region and helped form a club (Grand Order of the Iroquois) to promote the interests to the local group, the Iroquois. With the help of his Seneca friend Ely S. Parker of the Tonawanda Creek Reservation, he studied the culture of the Iroquois and produced the book, The League of the Ho-de-no-sau-nee or Iroquois (1851). Other works include, Ancient Society (1877), Systems of Consanguinity and Affinity of the Human Family (1870), and Houses and House-lives of the American Aborigines (1881).

Like Herbert Spencer and Edward Burnett Tylor, Morgan was a proponent of social evolution. He proposed a unilinear scheme of evolution from primitive to modern, through which he believed societies progressed. His evolutionary views of the three major stages of social evoluton, savagery, barbarism, and civilization, were proposed in Ancient Society. Although his specific evolutionary scheme has been discredited, the evolutionary position remains a vital part of anthropology. It also had an important influence on Marxist philosophy.

Morgan's other books, articles, and lectures established the study of kinship and family organization or recorded the culture of the various tribes he visited duting his lifetime.

He was an adopted member of the Iroquois tribe with the name Tayadaowuhkuh, meaning bridging the gap (between the Iroquois and the whites). In 1879 he was elected the president of the American Association for the Advancement of Science. He died in Rochester, New York two years later.

An annual lecture memorializing Morgan is given each year by the Anthropology Department of the University of Rochester.