Mustangs are wild horses that roam primarily on public land in Nevada, Utah, Wyoming, Colorado, Idaho, Montana, Oregon, California, Arizona and New Mexico. The wild horses come in a variety of shapes, colors and sizes. The word mustang is derived from the Spanish word Mesteno meaning, ownerless or stray horse. Over 100 years ago there were an estimated 2 million mustangs roaming the range. Only approximately 25,000 mustangs roam the United States today.