The National Trust will provide advice and both organisations will work with local stakeholders to develop a vision for the estate.
The arrangement is subject to the cabinet agreeing proposals tomorrow (Tuesday 26 March).
Work over the coming year will include forming a coalition of partners from public, private and voluntary sectors to realise the vision, engage in consultation with all of those involved and the preparation of funding bids to the Heritage Lottery Fund and other bodies.
Cabinet member for finance and management, councillor John Harrison, said:
"After many years of seeking a viable, long-term solution for Elvaston Castle and Country Park, I believe that working with the National Trust will deliver what the council and local people want - a sustainable, long term solution.
"I will therefore be recommending to my Cabinet colleagues that we grasp this opportunity to work with the National Trust - after all they are the nation's experts in managing historic buildings and estates successfully. Elvaston has much to offer and we need their expert advice to make the most of the potential of the Castle and Country Park."
He added: "We also need to find a solution that costs the tax payer less while still offering free public access to the country park. We will be consulting with all interested local groups about how they could be involved in the future."