The Norwegian First Division, also called 1. divisjon and OBOS-ligaen (named sponsor is property developer OBOS), is the second-highest level of the Norwegian football league system. Each year, the top finishing teams in the 1. divisjon are promoted to the Eliteserien, and the lowest finishing teams are relegated to 2. divisjon.
1. divisjon was previously known as 2. divisjon (1963–1990) and replaced regional league Landsdelsserien (1951–1962) after the latter was dissolved after the 1961–62 season. The second tier was also prior to Landsdelsserien known as 1. divisjon (1948–1951). Formally, it was a semi-professional league. The tier has been restructured many times and consists of 16 teams at present.
This page also has a version in other languages : ОБОС - лига (russian)