Though the length from its headwaters in Colorado to the Gulf of Mexico varies as its course changes, in the late 1980s, according to the International Boundary and Water Commission, qv its total length was 1,896 miles. The official border measurement ranges from 889 to 1,248 miles, depending on how the river is measured. In a sense, the Rio Grande is two streams. Its principal tributaries are the Pecos, Devils, Chama, and Puerco rivers in the United States, and the Conchos, Salado, and San Juan in Mexico. The two cities would constitute one of the world's major metropolitan areas if the Rio Grande did not divide them.
Principal crops vary along the river.
Colorado and northern New Mexico grow potatoes and alfalfa. Southern New Mexico and West Texas specialize in cotton, peppers, onions, and pecans. The lower Rio Grande valley qv raises citrus fruits, vegetables, and cotton. Agriculture and cattle raising are the leading industries along the entire Rio Grande, although maquiladoras qv are rapidly becoming the leading employer, especially in Mexico. The Rio Grande has never been navigable except near its mouth and, on rare occasions, to Laredo.