Organisers were forced to look for a new venue after doubts arose over the availability of the proposed Pow Beck Stadium in neighbouring Whitehaven.
Officials say they received several bids but were keen to keep Scotland's Group C games against Tonga and Italy in West Cumbria, and Workington secured the rights after Allerdale Borough Council, supported by Britain's Energy Coast, decided to invest £450,000 to upgrade Derwent Park.
Tournament director Nigel Wood said: "One of the stated values for RLWC2013 is passion for the game and we believe that is reflected by rugby league fans across West Cumbria, so this is great news for those fans above all.
"We know that there will be a challenge for the Workington host consortium to prepare Derwent Park for the tournament.
"But we have been rigorous in our examination of the proposal from Allerdale Borough Council, Britain's Energy Coast and Workington Town and we strongly believe that their level of commitment and the £450,000 investment will make West Cumbria a great part of RLWC2013."