Crow has added her name to a letter to United States politicians demanding a moratorium on wild horse musters, and raising concerns over a proposed northern Nevada muster in the so-called Calico Complex that would see 2500 horses taken from the wild.
More than 100 organisations have signed the letter, including actors Ed Harris and Wendie Malick.
"With one voice we are insisting that our government stop managing these beautiful and important animals to extinction," Crow said.
"It's time for all of us to speak up for our Wild Horses and Burros so we do not lose these living legends and inspiring symbols of our freedom in America," she said.
The signatories want a moratorium until a long-term and humane policy to manage the animals is developed.
The groups have concerns over Bureau of Land Management proposals to move horses further east and the current practice of removing horses and burros entirely from public lands specifically designated for the animals by Congress in 1971.
Crow urged US President Barack Obama and Interior Secretary Ken Salazar to stop musters.
"We request that the government and bureau begin to work in good faith with wild horse advocates for a sustainable solution.
"The Calico Roundup, scheduled to begin in December and continue through the dead of winter, is inhumane and must be stopped," she said.
So far, more than 7000 submissions have been received on the Calico roundup.
The groups point to the more than 33,000 wild horses already held in government holding facilities, costing $US100,000 a day.
"We already have enough wild horses in pens," said Ginger Kathrens, executive director of the Cloud Foundation.
"Adding more horses to those already held in confinement, when they are much safer on the range is short-sighted, inhumane and fiscally irresponsible."
The bureau is understood to be paying a private contractor $US610 per horse rounded up for an estimated total of nearly $US2 million for the Calico roundup alone.
Branding, vaccinating, sterilising and processing of horses to be placed in government holding facilities will cost several million more.
Wild horse advocate Julianne French accused the US Government of acting in defiance of the spirit and intent of the 1971 Free Roaming Wild Horses and Burros Act.
The act preserves wild horses and burros in over 300 areas of publicly owned rangeland in the west, forbidding their exploitation, harassment and removal.
Only 30 million acres remain of the 54 million acres designated primarily for wild horse use in 1971. More than 100 herds have been completely removed by the bureau and the groups fear some remaining herds are too small to ensure their long-term survival.