A line dance is a sequence of individual steps, but danced by a group of people in lines with no regard to gender balance.
They face in the same direction, where they are instructed with the steps, until they are used to them.
As they are not in contact with each other, but they use the same steps as everyone else. This gives it similarities to country and western dances and also uses similar music.
With simple steps and no physical contact with each other, it is ideal for none dancers and singles.
It all seemed to start in the late 1950's, whereby the Madison became a popular line dance, then in 1961 the San Francisco Stomp became popular also.
By the 1980's, there were more than ten dances, being danced as country dances, even though there were no defining points for music and dance, with western fashion and culture. Disco dance variations were early adaptions of dances, being used then.
Western dancing in lines became more popular with the 1992 hit, Achy Breaky Heart by singer Billy Ray Cyrus.
Max Perry a choreographer, had a hit dance in 1994 with the 'Swamp Thang' influenced by the group The Grid, with their song, 'Swamp Thing'. This techno song, that used banjo sounds in the melody, helped to start styles, other than country and western.
It so influenced the popularity of the dance in the mid 1990's, that Chet Atkins was quoted as saying, the music has gotten pretty bad, I think it is all that dam line dancing.
Jo Thompson, Scot Blevins and Max Perry, also several others, took the interest in the dances further, by using ballroom rythms and techniques.
There was more interest created outside the USA with the dance song, 126.96.36.199 by the band. 'Steps' in 1998.
Also Dwight Yoakams version of. 'Crazy Little Thing Called Love', in 1999. Many dancers used this song to practice with.
It would seem, that the most popular line dance then was the Cha Cha Slide.
The range of dances being used, puts most of them into what has been described as modern line dancing, although there were many styles of these.
Even as late as 2016, there is now a Gangnam style line dance.
If you are not sure, try a few different styles.