Formerly known as the National Women's Hockey League from 2015-2021, the Premier Hockey Federation is the top-tier professional women's hockey league in the world. The league was established as the NWHL in 2015 with four teams based in the northeast United States, the league eventually expanded as far west as Minnesota and finally into Canada with the Toronto Six in 2020. The PHF season ends with the Isobel Cup Playoffs and Championship, the Isobel Cup is named for Lady Isobel Gathorne-Hardy, the daughter of Frederick Stanley who is the namesake of the NHL's Stanley Cup.
