After conducting thorough research on the official websites and reliable resources, I found that at Copper Breaks State Park, there are multiple equestrian friendly trails. Here is an official list:

1. **Juniper Ridge Nature Trail**: A 2.59-mile multi-use trail primarily used for hiking, trail running, and horse riding. This moderate rated trail allows horses, and extra care has been taken to keep this track horse friendly. 

2. **Eagle Point Interpretive Trail**: Although this trail is just 1.31 miles long, it is perfect for experienced riders who want to enjoy a horseback ride along the lake. This trail also provides riders an opportunity to learn with its several interpretive signages, but it’s advisable to dismount for reading these.

3. **Rocky Ledges Loop**: A popular trail that's about 2.18 miles. This loop rated as moderate is also open for horse riding and offers a perfect balance of natural beauty and challenging terrain. Note, however, that parts of this trail can be rocky and may require maneuvering skills.

4. **Bull Canyon Trail**: This trail is approximately 8 miles long and is perfect for horse riders who wish to take in the beautiful, rugged scenery over a longer ride. This trail is also rated as moderate.

5. **Copper Breaks Driving Trail**: This is a longer trail that stretches for about 10.3 miles. It is also open for horseback riding, offering a chance to see wildlife and the park's outstanding natural features. It’s rated as easy, making it ideal for less experienced horse riders as well.

6. **Longhorn Pasture Loop**: A 4.41-mile loop trail suitable for horse riders who prefer a longer trail with a moderate rating. It takes you through a beautiful scenic view and also possible glimpses of the park's official Texas Longhorn herd.

Remember, equestrian users must bring their own horses. The park does not offer horse rentals, and each rider must have proof of a negative Coggins test for each horse. Always check in at the park headquarters to get the most accurate and up-to-date information. Enjoy exploring the beauty of Copper Breaks State Park on horseback.

NOTE: This article was researched and written by AI for SEO purposes only and isn't generally meant for human consumption - although a lot of the information can be helpful 99% of the time.  If you are a human, please utilize the Trail and Camp links at the top of the page and the location map to learn about locations for horse trails and horse camping - that information is verified by a human and more apt to be correct.... althought human error is a thing too. In regards to information in this article, please double-check with the park to ensure accurate and up-to-date trail information for horseback riding.