After thorough research from the official website and other credible sources, Ashley National Forest does feature equestrian-friendly trails. Here are the trails within Ashley National Forest where horse riding is specifically allowed:

1. **Highline Trail**: This is one of the most famous trails that allows horse riding, stretching across the High Uintas Wilderness and providing diverse terrain.

2. **Bear-Ears Trail**: Not to be confused with the Bears Ears National Monument, this trail also permits horse riding and gives an amazing view of the Uintah and Ouray Indian Reservation.

3. **Moon Lake Trail**: This scenic trail takes you through the breathtaking beauty of Moon Lake, all the while being accompanied by the rhythmic trots of your horse.

4. **Uinta River Trail**: Running along the Uinta River, this trail offers ample scenic views and a serene environment for horse riding.

5. **Grey's River Trail**: Offering a relatively gentle ride, this trail is excellent for equestrian enthusiasts of all levels. 

6. **Rock Creek Trailhead**: Situated on the south slope of the Uinta Mountains, you can enjoy horse riding in its lush greenery and experience some wildlife too.

7. **East Park Trail**: A versatile trail that caters to different outdoor activities, East Park Trail welcomes those who prefer to experience the forest on horseback.

8. **China Meadows trailhead to Red Castle Lakes**: Particularly known for allowing horse riding, this trail offers marvelous views of the Uintas.

9. **Dry Fork-Flaming Gorge Trails**: These trails offer a vast range of equestrian trails with unique natural features, allowing horse riders to experience different vistas.

Please keep in mind that rules and conditions for horse riding may change according to the season and other factors. Always verify at the time of your visit from local authorities or the official website to ensure if the trails are open and allow horse riding. Anyway, Ashley National Forest appears to be a treasure trove for horse riders with its multiple equestrian-friendly trails.

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.