The Colombian Massif (from the Spanish Macizo Colombiano) also known colloquially as Nudo de Almaguer refers to a group of mountains within the Andes of south central Colombia. The massif is mainly within the area of the Cauca, Huila, and Nariño Departments. To the south is the Pasto Massif (Nudo de los Pastos) and to the north begins the Central and Eastern Andes.
The total area is 32,682 km² (12,619 mi²) which are distributed as follows: 13,716 km² (5296 mi²) of forests, 15,423 km² (5955 mi²) of agroecosystems, 2567 km² (991 mi²) of páramos, 43 km² (17 mi²) of nival (snow) zone, 924 km² (357 mi²) have xerophytic vegetation and 9 km² (3 mi²) of urban settlements. The altitude varies between 2600 and 4700 MASL (8530 ft and 15,420 ft).
This is area is identified as the source of 70% of the Colombian safe water for human consumption and irrigation. The headwaters of the Magdalena and Cauca Rivers (Caribbean slope), Caquetá and Putumayo Rivers (Amazon Basin) and the Patía River (Pacific slope).
The massif contains 362 high mountain bodies of water, 13 páramos and other ecosystems rich in flora and fauna. From south to north are the páramos of Cutanga, Letero, Las Papas (Potatoes), Apio (Celery) and Buey (Ox). Sotará and Puracé are the prominent volcanoes of the area, the latter being with the Puracé National Natural Park.
Very few people have traversed the mountains of this region because it is covered by rugged mountains and an impenetrable and cold páramo environment, both of which are natural guardians which preserve the great water supply that provides water for half of Colombia before emptying into the sea.