The Orinoco is one of the longest rivers in South America at 2,140 km, (1,330 miles). Its rainage basin, sometimes called the Orinoquia (especially in Colombia) covers 880,000 km², 76.3% in Venezuela with the rest in Colombia. The Orinoco and its tributaries are the major transportation system for eastern and interior Venezuela and the llanos of Colombia. However, since river navigation is declining in every country, many of the old waterways along the Orinoco watershed are now an obstacle to land communications more than a useful commercial route.