After online research based on sources including the official National Park Service page, a list was compiled of the horse trails in Lassen Volcanic National Park. Here is the information in a list-style article:

**Title: Horseback Riding on Trails at Lassen Volcanic National Park**

1. **Pacific Crest Trail (PCT)**: The northern part of the PCT that runs through the park is open to horseback riding. With its breath-taking views and rugged terrain, PCT offers a challenging yet rewarding ride for horses and their riders.

2. **Butte Lake to Snag Lake Loop**: Known for its striking volcanic features and pines, this trail welcomes horses. The loop reckoned for its moderate difficulty, offering a mix of terrain for experienced horse riders.

3. **Juniper Lake to Horseshoe Lake**: This scenic trail also permits horses and has abundant vistas of the park's mesmerizing landscape. 

4. **Summit Lake Trail**: Horse riders can also enjoy the Summit Lake Trail, a serene trail with abundant natural features. 

5. **Twin Meadows Trail**: The Twin Meadows Trail is known for its lush meadows and mountain views, a worthwhile endeavour for any horse rider. 

6. **Hat Creek Trail**: On the Hat Creek Trail, horses can be used to traverse the range of geologic features that this captivating route has to offer.

For a seamless riding experience, horse riders are however advised to stick to designated horse camps such as Juniper Lake Horse Corral, Butte Lake Corral, and Summit Lake Corral. These corrals contribute to the sustainability of the park's trail system by reducing soil erosion and minimizing conflicts between different trail users. 

Additionally, riders are encouraged to follow trail etiquette, which includes checking if a trail or trail segment allows horses, not leaving horses unattended on trails, and practicing Leave No Trace principles. 

Explore these horse trail options in Lassen Volcanic National Park for an unforgettable equestrian adventure!

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.