How long is the Back 40? The signature outer loop is ~21 miles, with many interior miles to customize your ride. By cdavis|2025-09-30T13:31:02-06:00September 30, 2025|Back 40| Share This Story, Choose Your Platform! FacebookXRedditLinkedInWhatsAppTelegramTumblrPinterestVkXingEmail About the Author: cdavis