The Heartland series is about a barn in Virginia that rehabilitates hurt and abused horses. As the book says, "Heartland is a horse farm nestled in the hills of Virginia, but it's much more than that. Heartland is like no other place- it's a place where the scars of the past can be healed, a place where frightened and abused horses learn to trust again."
The main character is Amy Flemming. Amy's mother dies after a tragic accident and she is left to run Heartland with her grandfather and to make amends with her estranged father and sister. The series follows Amy, her family, and other friends; we see relationships grow and others come to end and we see the healing of many horses along the way.
While this book is targeted towards younger adolescent girls, I think girls of all ages can benefit from reading this book. The plot line sucks you in from the very first pages and
The book series was made into a television series in Canada. While many plot points and characters have been changed to attract an older audience, the basic ideas and themes of the Heartland books are still there.
You can check out the books here and here.
And you can learn more about the television series here.