After conducting extensive research from the official Washington State Department of Natural Resources (DNR) website, it's noted that Capitol State Forest offers numerous horse-friendly trails. Below is a list of horse-friendly trails in the Capitol State Forest that have been confirmed from the official source:

1. **C-Line Trail**: This trail is multi-functional, which means it has sections that are specifically created for horse riding.

2. **Waddell Basin West Trail**: This trail is situated in the western part of the Waddell Basin and makes for an enjoyable ride on horseback.

3. **Greenline Trail**: This trail offers a combination of challenging terrains and tranquil forest scenery. Keeping the interest of horse riders in mind, it includes a special horse-friendly section.

4. **Margaret McKenny Campground Loop**: This loop is well-designed and welcomes horses. It is often a favorite amongst horse riders visiting the Capitol State Forest.

5. **Mima Falls Trail**: Horse riders frequently use this trail due to its fantastic views and diverse landscapes.

6. **Sherman Valley Trail**: This is a great trail for a leisurely horse ride through peaceful forest settings.

7. **Fall Creek Trail**: This trail is welcoming to horses and provides great opportunities to experience the forest's serene beauty.

8. **Mima Porter #8 Trail**: This trail is specifically marked as multi-use, with horse trails being one of its contributions.

9. **Crestline Trail**: This trail is also horse-friendly, providing fantastic opportunities for riders to explore the forest on a broader scale.

10. **Wedekind Trail**: This trail has been named as a mixed-use trail specifically allowing for horse riding.

All these trails are verified to be horse-friendly and are equipped with the necessary amenities to ensure a safe and enjoyable ride for both the horse and the rider. Please follow all posted rules and guidelines to ensure the trails remain safe and enjoyable for all users. Happy riding!

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.