CSN is the third studio album by Crosby, Stills & Nash, released on Atlantic Records on June 17, 1977. It is the group's second studio release in the trio configuration. It peaked at No. 2 on the Billboard Top Pop Albums chart; two singles taken from the album, Nash's "Just a Song Before I Go" and Stills' "Fair Game" charted on the Billboard Hot 100. It is currently the trio configuration's best selling record, outselling 1969's Crosby, Stills & Nash by 200,000 copies. It has been certified quadruple platinum by RIAA.

Crosby, Stills & Nash (CSN) was a folk-rock supergroup made up of the American singer-songwriters David Crosby and Stephen Stills and the English singer-songwriter Graham Nash. When joined by the Canadian singer-songwriter Neil Young, they were called Crosby, Stills, Nash & Young (CSNY). They are noted for their intricate vocal harmonies and lasting influence on American music and culture, their political activism and their tumultuous relationships.