[1] The Northeastern tradition, descended from the 18th-century cotillion and the 19th-century quadrille, comprises primarily figures in which the action is initiated by a facing pair of couples, either the heads or sides.
Many of the basic movements (such as "ladies chain" and "right and left") that make up the figures are common to the entire Northeastern repertoire.
As in its ancestors the cotillion and quadrille, the movements in this style of square dance are synchronized with the phrases of the music.
The structure is not dependent on the four-couple square formation, and the dance is often done in a large circle containing any number of couples.
The Western tradition appears to have developed as settlers from the eastern United States took their local dance forms along as they moved west.
Areas where traditional Western squares have been documented include Iowa, Nebraska, Colorado, Texas, and Arizona.
In areas that were settled by Europeans relatively early, such as New England and eastern Canada, the piano is the mainstay of square dance rhythm and chording.
In the Southern United States and along the path of westward expansion, instruments like the banjo and guitar, which are more portable and easier to make and repair than the piano, were and are more common.
Certain instruments are popular in specific regions; examples include the accordion in Quebec and Newfoundland and the hammered dulcimer in Michigan and Upstate New York.
In some communities where square dancing has survived, the prevailing form of music has become popular songs from the 1930s, 1940s and 1950s, played on instruments such as saxophones, drums, and electric guitars.
Many traditional dance tunes retain the binary form of classical dance, following an "AABB" pattern of two distinct strains played twice each, the "A part" and "B part" typically being 8 measures (16 downbeats) in length, making one playing of the tune 32 measures (64 downbeats).
In the northeastern United States, traditional square dances are frequently done to popular songs in addition to, or instead of, jigs and reels.
"Survival" dances are typically either run by a band or caller as a profit-making enterprise, or sponsored by a non-dance organization (such as a church, a Grange, or a fire department) as a social service and/or a fundraiser for its other activities.