Question: Williamsport, Arizona is on the bank of one of the  principal rivers of the Southwestern United States and northern Mexico that is how long

full_context: Document 1: La Colorada, Mexico: La Colorada is a small town in La Colorada Municipality in the Mexican state of Sonora. In 2005, the population of the municipality was 1,754, with 288 living in the municipal seat. Formerly known as Minas Prietas, La Colorada became a municipality on June 28, 1934. As an important mining camp in Mexico, La Colorada boasted a population that topped 5,604 in 1895. The municipality is situated 45 km (29 mi) southeast of Hermosillo.
Document 2: Bill Williams River: The Bill Williams River is a 46.3 mi river in west-central Arizona where it, along with its tributary, the Santa Maria River, form the boundary between Mohave County to the north and La Paz County to the south. It is a major drainage westwards into the Colorado River of the Lower Colorado River Valley south of Hoover Dam and Lake Mead, and the drainage basin covers portions of northwest, and west-central Arizona. The equivalent drainage system paralleling the east–west lower reaches of the Bill Williams is the Gila River, which flows east-to-west across central Arizona, joining the Colorado River in the southwest at Yuma. The confluence of the Bill Williams River with the Colorado is north of Parker, and south of Lake Havasu City.
Document 3: Colorado River (Texas): The Colorado River is an 862 mi long river in the U.S. state of Texas. It is the 18th longest river in the United States and the longest river with both its source and its mouth within Texas.
Document 4: Williams Air Force Base: Williams Air Force Base is a former United States Air Force (USAF) base, located in Maricopa County, Arizona east of Chandler, and about 30 mi southeast of Phoenix. The area has since been annexed by the city of Mesa. It is a designated Superfund site due to a number of soil and groundwater contaminants.
Document 5: South Platte River: The South Platte River is one of the two principal tributaries of the Platte River. Flowing through the U.S. states of Colorado and Nebraska, it is itself a major river of the American Midwest and the American Southwest/Mountain West. Its drainage basin includes much of the eastern flank of the Rocky Mountains in Colorado; much of the populated region known as the Colorado Front Range and Eastern Plains; and a portion of southeastern Wyoming in the vicinity of the city of Cheyenne. It joins the North Platte River in western Nebraska to form the Platte, which then flows across Nebraska to the Missouri. The river serves as the principal source of water for eastern Colorado. In its valley along the foothills in Colorado, it has permitted agriculture in an area of the Colorado Piedmont and Great Plains that is otherwise arid.
Document 6: Rio Grande: The Rio Grande ( or ; Spanish: Río Bravo del Norte , ] or simply Río Bravo) is one of the principal rivers in the southwest United States and northern Mexico (the other being the Colorado River). The Rio Grande begins in south-central Colorado in the United States and flows to the Gulf of Mexico. Along the way, it forms part of the Mexico–United States border. According to the International Boundary and Water Commission, its total length was 1896 mi in the late 1980s, though course shifts occasionally result in length changes. Depending on how it is measured, the Rio Grande is either the fourth- or fifth-longest river system in North America.
Document 7: Minto City: Minto City, often called just Minto, sometimes Minto Mines or Minto Mine, was a gold mining town in the Bridge River Valley of British Columbia from 1930 to 1936, located at the confluence of that river with Gun Creek, one of its larger tributaries. It was first called the Alpha group of claims in the 1920s, when underground miners were exploring the seams of Cadwallader Creek and the origins of the placer deposits downstream in the Bridge River. The mine prospect was never much successful although a model townsite was built by promoter "Big Bill" Davidson, who imported soil to build a specially-built rodeo ground and baseball diamond on the rocky site. The larger mine of Bralorne was nearby. The mine shut down in 1936 due to productivity issues, but restarted in 1940. The valley has since been significantly altered when most of the vestiges of the town were inundated by the waters of the Carpenter Lake reservoir following completion of the Bridge River Power Project. The town sat on the western end of the lake near the present Carpenter Lake Road (a section of BC Road 40), part of the road drove through a wooden Tudor arch built into the rock mill.
Document 8: Colorado River Aqueduct: The Colorado River Aqueduct, or CRA, is a 242 mi water conveyance in Southern California in the United States, operated by the Metropolitan Water District of Southern California (MWD). The aqueduct impounds water from the Colorado River at Lake Havasu on the California-Arizona border west across the Mojave and Colorado deserts to the east side of the Santa Ana Mountains. It is one of the primary sources of drinking water for Southern California.
Document 9: Colorado drainage basins: The U.S State of Colorado includes the headwaters of several important rivers. The state is divided into two major hydrographic regions by the Continental Divide of the Americas. East of the Continental Divide, surface waters flow via the South Platte River, the North Platte River, the Republican River, the Arkansas River, the Cimarron River, the Canadian River, or the Rio Grande to the Gulf of Mexico. West of the Continental Divide, surface waters flow via the Green River, the upper Colorado River (formerly the Grand River), or the San Juan River into the Colorado River and on to the Gulf of California. Colorado also has three significant endorheic basins: the San Luis Closed Basin in the San Luis Valley, and the Bear Creek Basin and the White Woman Basin spanning the Colorado-Kansas border north and south of the Arkansas River.
Document 10: South-Central Colorado: South-Central Colorado is a region of the U.S. state of Colorado. It can be roughly defined by Chaffee County in the northwest, El Paso County in the northeast, Las Animas County in the southeast, and Conejos County in the southwest. Some notable towns and cities there include Colorado Springs, Pueblo, Cripple Creek, Cañon City, Salida, Buena Vista, Monte Vista, Alamosa, Walsenburg, and Trinidad. The landscapes of South-Central Colorado were made known to the Western world by the explorations of Zebulon Pike and Kit Carson, who were later followed by settlers, many of whom came by the Santa Fe Trail. The upper tributaries of the Arkansas River and South Platte River provide ample whitewater rafting and are famous for trout and bass fishing in scenic settings such as Royal Gorge. Much of the local economic system is dependent on mining, forestry, ranching, and tourism related to these endeavors. South-Central Colorado has so far largely escaped urbanization, allowing visitors to experience something of the American Old West.
Document 11: Colorado River: The Colorado River is one of the principal rivers of the Southwestern United States and northern Mexico (the other being the Rio Grande). The 1450 mi river drains an expansive, arid watershed that encompasses parts of seven U.S. and two Mexican states. Starting in the central Rocky Mountains in the U.S., the river flows generally southwest across the Colorado Plateau and through the Grand Canyon before reaching Lake Mead on the Arizona–Nevada border, where it turns south toward the international border. After entering Mexico, the Colorado approaches the mostly dry Colorado River Delta at the tip of the Gulf of California between Baja California and Sonora.
Document 12: Calico, San Bernardino County, California: Calico is a ghost town and former mining town in San Bernardino County, California, United States. Located in the Calico Mountains of the Mojave Desert region of Southern California, it was founded in 1881 as a silver mining town, and today has been converted into a county park named "Calico Ghost Town". Located off Interstate 15, it lies 3 mi from Barstow and 3 miles from Yermo. Giant letters spelling "CALICO" can be seen on the Calico Peaks behind the ghost town from the freeway. Walter Knott purchased Calico in the 1950s, architecturally restoring all but the five remaining original buildings to look as they did in the 1880s. Calico received California Historical Landmark #782, and in 2005 was proclaimed by then-Governor Arnold Schwarzenegger to be California's Silver Rush Ghost Town.
Document 13: San Juan River (Colorado River): The San Juan River is a major tributary of the Colorado River in the southwestern United States, providing the chief drainage for the Four Corners region of Colorado, New Mexico, Utah and Arizona. Originating as snowmelt in the San Juan Mountains (part of the Rocky Mountains) of Colorado, it flows 383 mi through the deserts of northern New Mexico and southeastern Utah to join the Colorado River at Glen Canyon. The river drains a high, arid region of the Colorado Plateau and along its length it is often the only significant source of fresh water for many miles. The San Juan is also one of the muddiest rivers in North America, carrying an average of 25 million US tons (22.6 million t) of silt and sediment each year.
Document 14: Carpenter, Colorado: Carpenter is a ghost town in Mesa County, Colorado, United States, twelve miles northeast of Grand Junction at the end of an extension to 27¼ Road. The settlement was established by William Thomas Carpenter early in 1890 to provide the miners who worked in his two Book Cliff mines with a place to live. He began building shacks to house his single miners and later erected small houses for the employees with families. As a result of the town's rapid growth, a request to the U.S. post office to establish a branch there in June 1890 was quickly obliged and the community was officially dubbed Carpenter. However, the town never attained a population of over 50, and the post office closed its doors after only a year. After the closure of its post office, Carpenter built a company store and a combination boarding house/restaurant. Book Cliff company stone cutters and masons constructed several buildings and many foundations at Carpenter, using stone from the company quarry near the cliffs. One of the finest examples of a building made of Book Cliff sandstone is the Fruita, Colorado Catholic church. Several years of prosperity followed the arrival of the Little Book Cliff Railway at the townsite in 1892. Carpenter began to formulate big plans for his village. He envisioned it as a tourist resort complete with hotel, dance pavilion, picnic areas, and even a lake that was to be fed by a spring located near his Book Cliff mines. Carpenter renamed the camp "Poland Spring" after a noted resort of that name in Maine. It was variously referred to as Polen, Pollen, and Polan Springs, despite the fact that Carpenter’s intended name was evidenced by his having it emblazoned on the side of one of his railroad excursion cars. The resort plans were never completed because Carpenter went broke shortly after the Panic of 1893. Isaac Chauncey Wyman, a wealthy Massachusetts investor, became the next owner of the Book Cliff company. The town continued to enjoy an active existence because he did much to improve the mines and thus created a need for additional employees. The old eating house, referred to as the "Hotel de Carpenter" on occasion, was converted into a school and church for the camp’s inhabitants, and many company structures were rebuilt and improved during Wyman’s tenure as owner. The new name "Book Cliff" was applied to the town but did not adhere any better than did Poland Springs. Usually people referred to the place as the “Book Cliff Mines.” The town reached its zenith and then began a gradual decline following Wyman’s death in 1910. In his will Wyman left the town, railroad, and mines to Princeton University. Princeton managed everything for 15 years then decided to abandon it all in 1925. By the end of that summer nearly everything had been sold, dismantled, and hauled away.
Document 15: Williamsport, Arizona: Williamsport, is a former mining town and present day ghost town, on the bank of the Colorado River in La Paz County, Arizona.
ground_truth: 1450 mi