When confronted with the question of tribal existence, courts adjusting land claims under the Nonintercourse Act have employed a definition of tribe developed by the Supreme Court in Montoya v. United States. The definition states that a 'tribe' is a body of Indians of the same or a similar race, united in a community under one leadership or government, and inhabiting a particular (though sometimes ill-defined) territory. Unfortunately, this definition fails to account for the disintegrating influences that loss of land has had on the tribe. The appropriateness of the legal definition was first questioned by the Mashpee tribe in 1979. In Mashpee Tribe v. New Seabury Corp., in which a significant number of tribal members lost their land, the court failed to recognize that the causal relationship between the Indians' loss of tribal land and a minimal amount of demonstrable political cohesiveness was antithetical to the protective purposes of the Act and the liberal policies of Indian law. A proposed alternative definition of 'tribe' corresponds to the concept of tribe as reflected in cases applying the Indian Claims Commission Act. It deemphasizes the importance of political cohesion and stresses the relevance of the Indians' self-image. Also, it acknowledges the possibilty of a causal relationship between the alleged injury and the present condition of the tribal structure. The validity of the proposed definition is enhanced by the new Bureau of Indian Affairs regulations. Most important, it acknowledges the loss of land and the present condition of a tribe's structure. Footnotes are provided.