The Premier Hockey Federation (PHF) was a women's professional ice hockey league in the United States and Canada that operated from March 2015 until June 2023. The league was established in 2015 as the National Women's Hockey League (NWHL), comprising four league-owned teams. Over time, some teams gained independent ownership and the number of teams grew to seven; teams during the league's final season in 2022–23 included the Boston Pride, Buffalo Beauts, Connecticut Whale, Metropolitan Riveters, Minnesota Whitecaps, Montreal Force, and Toronto Six. The Isobel Cup was awarded annually to the league playoff champion.
The PHF ceased operations on 29 June 2023, after the league and its intellectual properties were purchased by Mark Walter Group and BJK Enterprises, led by Mark Walter and Billie Jean King, respectively. Both businesses had entered a partnership with the Professional Women's Hockey Players Association (PWHPA) in May 2022, with the intent to create a new, unified professional women's ice hockey league in North America. On 29 August 2023, the partners announced the formation of the Professional Women's Hockey League (PWHL), which began play in January 2024.
