Spirit: Stallion of the Cimarron was released in 2002 by Dreamworks Animation. Produced by the same people who worked on Disney's The Lion King.
The movie itself was made using a mix of traditional and digital animation, more so than regular 2D films, and is seemingly the first of that kind.

The story follows a dun/buckskin kiger mustang named Spirit living in the wild Cimarron prairie.
Starting with Spirit from birth, he grows up to be the leader of his herd. After seeing a fire in the distance one night, something he's never seen before, he
races off to find out what it is. Unfortunately he's captured by the people and taken to a US Cavalry post.
Whilst there Spirit meets Little Creek, a young Lakota, also captured by the US Cavalry.

After escaping the Cavalry post after the Colonel and his men fail to break Spirit into being ridden by them Spirit is then taken by Little Creek and the other
Lakota's who also want to ride him. Here he meets Rain, a paint mare, who belongs to Little Creek.
After a battle between the Lakota's and the Cavalry, being captured again and made to drag a large train and finally helping Little Creek escape with his life
Spirit, joined by Rain, finally returns to his homeland.

In short, Spirit: Stallion of the Cimarron is a fantastic family film and deserves much more acclaim than it has received so far.