Holliday, 22, who signed three years ago from the Kells club, has agreed a new two-year deal with Haven.
Originally a centre he has been used principally as a second-row forward this season and has flourished.
Amanda Hewer, Whitehaven’s general manager said: “We are delighted to have Connor on board for next season as he has made excellent progress this season.”
Coach Carl Forster added: “Connor has been excellent for us this year and is the type of young player with great potential that we like to encourage.”
Whitehaven, although initially slow in announcing their signings because of the uncertainty of where they will be playing next season, are expected to unveil several more over the next few weeks.
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