The incident happened along the 200 block of Robin Red Breast Road in New Castle County.
Rescuers were dispatched around 1:30 p.m. and arrived to find that the animal had fallen through a small foot bridge.
Crews had to cut through the bridge in order to get the animal free.
The horse was transported to a veterinarian for evaluation and treatment.
Witnesses at the scene say the bridge appears to be made of metal but is actually made of plastic.
The bridge was built for bicyclists by the Delaware Trail Spinners, an area bike club.