OCTA has 11 regional or state chapters, many of which sponsor their own websites. The chapters work on marking and mapping the trails and work with private landowners as well as government agencies, such as the Bureau of Land Management and the National Park Service, on preservation issues. It's a great way to get “on the ground” in OCTA because local chapters sponsor trail outings in their area and have frequent meetings to discuss trail history and preservation. Most of these events are open to members and non-members alike.

Membership in regional chapters is voluntary, although in order to be a member of a local chapter you must be a member of national OCTA. Many members join local chapters to get the best available information about issues and projects in that area. Every chapter welcomes members from all over. Most publish their own newsletters. Visit the chapter websites to get more information about what the chapter in your area is doing.