Hockeyettan is the third tier of ice hockey in Sweden. As of the 2015–16 season, the league consists of 39 teams divided geographically into four groups. Hockeyettan operates a system of promotion and relegation with HockeyAllsvenskan and Division 2. From 1944 to 1975, Division I was the highest league in the Swedish ice hockey system, but with the creation of Elitserien (now the SHL) in 1975, it became the second tier.
https://en.wikipedia.org/wiki/Hockeyettan