Includes everything in the state (departamento) of Antioquia, of which Medellín is the capital city and biggest airport. The canyons here are perhaps the best equipped in the country and best bet if you are not brining a hammer drill and bolt kit.
To the east of Medellín there are many established canyons, 3 in San Carlos, 1 in San Luis, 1 in San Francisco, 1 in Cocorna. Each can be done in a day trip from Medellín.
Jardin, to the southwest of Medellín 3 hours by car, contains several very nice established canyons and two guide companies.
As is typical in the jungle rainforest, it rains almost on a daily basis in Antioquia and the rain can pour down in short downpours that can elevate water levels in a short time. Thus, all of the canyons can quickly turn into X-rated on any given day. Great care should be taken in watching weather patterns.