Llanos, the Spanish word for “plains.” More specifically, the word refers to the vast plains covering about 225,000 square miles (583,000 km2) of the Orinoco River basin in Venezuela and Colombia. Most of the region lies less than 600 feet (180 m) above sea level and is flat to gently rolling. Tall, coarse grasses and scattered trees, growing singly or in small stands, cover most of the llanos.

The climate is tropical, with distinct wet and dry seasons. Extensive flooding occurs during the wet season; severe droughts often mark the dry. Disease-bearing insects make the region unhealthful.

With few exceptions the llanos are sparsely inhabited. The only sizable cities are Ciudad Bolívar and Ciudad Guayana, on the lower Orinoco River in Venezuela. Longtime inhabitants of the region, called llaneros, are of mixed Spanish, Indian, and Negro descent. Many are skilled horsemen, and cattle raising is the chief economic activity of the llanos. Petroleum is also produced.