National League 1, (which was known before September 2009 as National Division Two), is the third level of domestic rugby union competition in England. It was known as Courage League National Division Three when founded in 1987. This is the lowest level of the English rugby union league system which is nationwide. The league consists of sixteen teams with all the teams playing each other on a home and away basis to make a total of thirty matches each. There is one promotion place and three relegation places. The champions are promoted to the Greene King IPA Championship and the bottom three teams are relegated to either National League 2 North or National League 2 South (formerly National Division Three North and South) depending on the geographical location of the team.
When the club system was introduced in 1987 the division was known as Courage League National Division Three. Ten years later, in 1997, the league was restructured and the Premiership was introduced, which consisted of the top two divisions. Therefore, National 3 became the top league outside of the Premiership structure, and was renamed as National 1. In 2000–01 the Premiership was reduced to a single division and National 1 was renamed National 2. Following the formation of the professional RFU Championship in 2009 the league, once again, became known as National League One, and is currently the lowest tier that is nationwide. The league previously consisted of fourteen clubs, but from 2009–10 increased to sixteen. Only one team is now promoted to the RFU Championship and since 2009–10 three teams are relegated to National League 2 North or National League 2 South.
When the league system was formed in 1987, the following teams participated in the league, which was known as National 3. Twenty-eight years on only two teams, Fylde and Plymouth Albion are currently playing at this level. (Updated to 2015–16)