List_of_longest_mountain_chains_on_Earth
The world's longest above-water mountain range is the Andes,[1][2] about 7,000 km (4,300 mi) long. The range stretches from north to south through seven countries in South America, along the west coast of the continent: Venezuela, Colombia, Ecuador, Peru, Bolivia, Chile, and Argentina. Aconcagua is the highest peak, at about 6,962 m (22,841 ft).
This list does not include submarine mountain ranges. If submarine mountains are included, the longest is the global mid-ocean ridge system which extends for about 65,000 km (40,000 mi).[3]