The Americans With Disabilities Act (ADA) is one of America's most comprehensive pieces of civil rights legislation that prohibits discrimination and guarantees that people with disabilities have the same opportunities as everyone else to participate in the mainstream of American life—to enjoy employment opportunities, to purchase goods and services, and to participate in State and local government programs and services.

To be protected by the ADA, one must have a disability, which is defined by the ADA as a physical or mental impairment that substantially limits one or more major life activities, a person who has a history or record of such an impairment, or a person who is perceived by others as having such an impairment. The ADA does not specifically name all of the impairments that are covered. The ADA is located in the United States Code, beginning at 42 U.S.C. §12101.

The ADA prohibits discrimination on the basis of disability in the activities of places of public accommodations (businesses that are generally open to the public and that fall into one of 12 categories listed in the ADA, such as restaurants, movie theaters, schools, day care facilities, recreation facilities, museums, libraries, parks, and doctors' offices). The ADA requires newly-constructed or altered places of public accommodation—as well as commercial facilities (privately owned, nonresidential facilities such as factories, warehouses, or office buildings)—to comply with the ADA Standards. Private clubs and religious organizations are exempt from the ADA's title III requirements for public accommodations.

In Montana, as in all states, the Americans with Disabilities Act (ADA) provides a framework to protect individuals with disabilities from discrimination in various aspects of public life. The ADA's protections extend to employment, where it requires employers to provide reasonable accommodations to qualified individuals with disabilities, unless doing so would cause undue hardship. It also mandates accessibility in public accommodations, such as restaurants, schools, and doctors' offices, ensuring that new or altered facilities meet ADA Standards for design. While the ADA is a federal law, Montana businesses and state and local government entities must comply with its provisions. However, private clubs and religious organizations are exempt from Title III, which covers public accommodations. It's important to note that the ADA's definition of disability is broad, covering not only those with physical or mental impairments that substantially limit major life activities but also those with a history of such impairments or who are perceived by others as having such impairments.