Below: Pickens talks about the Wild Horse Eco-Sanctuary plan:
The aim was to get all 36,000-plus horses out of holding soon after and on to a massive ranch, which has already been secured.
Pickens and her supporters have campaigned vigorously around the vision of a massive wild horse sanctuary in the western rangelands where wild horses currently held captive in federally funded holding facilities can run free.
Their two-and-a-half-year campaign is now on the brink of delivering the much-vaunted sanctuary, although details of how the public-private venture will be funded have yet to be released.
The growing numbers of wild horses held in captivity has placed a massive strain on the bureau's budget, commanding the lion's share of the funding allocated to the wild horse and burro programme.
"Our mustangs are getting their sanctuary and we have the BLM's support," an ebullient Pickens announced.
"Over the past three days, I have been to meetings in Sacramento and again in Washington, DC. I've met with BLM director Bob Abbey, deputy director Mike Pool, along with the Wild Horse and Burro team.
"The BLM has officially agreed to support going forward with the development of the wild horse Eco-sanctuary for the horses in holding!" Pickens said.
"Also in DC, I met with Congressman Jim Moran, who had already given his blessing, but is submitting legislation to members of Congress on behalf of these wild mustangs.
"We are so thankful to him and his staff for their efforts on the wild horse and burro issue. All the meetings were fabulous and we could not be happier about the news.
"This final acceptance by the BLM this week was the hurdle we had yet to get over," she said.
"We are so thankful for the opportunity to start our pilot programme with 1000 horses, and we aim to get all 36,000-plus horses [out of] holding soon after.
"This action by the BLM shows great leadership on the part of Bob Abbey and Mike Pool for taking a stand for our beautiful mustangs and accepting the solution we have offered."
Pickens said the Saving America's Mustangs foundation - which she founded with the purpose of driving her sanctuary vision - offered its sincerest thanks for the "monumental co-operation" on the part of the BLM for an alternative to the holding pens.
"This is a truly a dream come true," she said.
Her plan, backed by the foundation, will see the horses rehomed on a massive reserve comprising private and public lands.
Pickens, on her website, said the only practical solution to finding a long-term home had been to involve a private foundation which owned private water rights and irrigated pastures.
"A public/private ranch can ensure a healthy herd thriving on healthy rangelands," she said.
Madeleine Pickens' Saving America's Mustangs foundation will own and operate a large ranch for the sole purpose of providing care and a perpetual home for wild horses.
The horse population would be managed as a non-reproductive herd.
The foundation expects it will be able to take an additional 2000 to 4000 animals annually from future government wild horse gathers.
It is hoped the sanctuary will eliminate the need for long-term federal holding facilities.
The ranch that will provide a new home to the mustangs comprises two-thirds high summer range and one third low winter range, combined with a large farming operation which provides ample year-round forage.
A river runs through the middle of the ranch with several large reservoirs and many hundreds of springs to provide abundant water for forage production, horses and wildlife.
The stocking level of horses will be phased in over time, starting with about 10,000 animals and increasing about 4000 animals per year until the appropriate stocking rate is reached.
This phase-in of stocking is necessary for additional forage production projects to come on line.
The maximum number of horses the ranch can support is near 30,000.
The ranch boundary is securely fenced. Fenced railroad and highway right-of-ways are major portions of the boundary.
The fenced boundary in the high country would not be pressured by large numbers of horses.
The high country boundary fences may be damaged as a result of winter snow and ice, but would be inspected and repaired prior to the horses returning to the high country each season. Agreements would be honoured to ensure a good neighbour policy.
Water sources are numerous on the ranch so there is no concern of horses limiting the availability of water for wildlife species.
Open spaces are plentiful for horses and wildlife in the spring, summer, and fall, but limited in the winter.
Most of the winter range is private land which will accommodate both horse and wildlife needs during the harsh winters of major snow events and sub-zero weather.
Elk, deer, and horses will concentrate on the private land winter range during these major winter events, which will be critical to their survival.