This is what we found on Wikipedia regarding the GAA Allianz League:

The National Football League (NFL; Irish: Sraith Náisiúnta Peile) is an annual Gaelic football competition between the senior county teams of Ireland plus London. Sponsored by Allianz, it is officially known as the Allianz National Football League.

The Gaelic Athletic Association organises the league. The winning team receives the New Ireland Cup, presented by the New Ireland Assurance Company. The National Football League is the second most prestigious inter-county Gaelic Football competition after the All-Ireland Senior Football Championship.

Unlike many league competitions in sport, each team plays the other teams in their division only once. Teams that meet in the same division over the course of a number of years often play on a home and away basis in alternative years, though this is not strictly adhered to. Once the divisional matches have been played, the latter stages of the league become a knockout competition for the top teams in each division. This is seen as good preparation for the upcoming All-Ireland Championship and there is usually more intensity to the division finals than those played earlier in the league, but still lacking the intensity of Championship matches.

Derry are the current league champions, having won the 2024 league.