Question: How many people cross the border over which the Chamizal dispute  took place?

full_context: Document 1: El Paso–Juárez: El Paso–Juárez, also known as Juárez–El Paso, the Borderplex or Paso del Norte, is a binational metropolitan area, or conurbation, on the border between Mexico and the United States. The region is centered on two large cities: Ciudad Juárez, Chihuahua, Mexico and El Paso, Texas, U.S. Additionally, nearby Las Cruces, New Mexico, U.S. is sometimes included as part of the region, referred to as El Paso–Juárez–Las Cruces or El Paso–Juárez–Southern New Mexico. With over 2.7 million people, this binational region is the 2nd largest metropolitan area (San Diego- Tijuana being the largest) on the United States–Mexico border. The El Paso–Juárez region is the largest bilingual, binational work force in the Western Hemisphere.
Document 2: Laredo, Texas: Laredo ( ; ] ) is the county seat of Webb County, Texas, United States, located on the north bank of the Rio Grande in South Texas, across from Nuevo Laredo, Tamaulipas, Mexico. According to the 2010 census, the city population was 236,091, making it the tenth-most populous city in the state of Texas and third-most populated on the Mexico–United States border, after San Diego, California, and El Paso, Texas. Its metropolitan area is the 178th-largest in the
Document 3: Geography of Mexico: The geography of Mexico describes the geographic features of Mexico, a country in the Americas. Mexico is located at about 23° N and 102° W in the southern portion of North America. From its farthest land points, Mexico is a little over 3,200 km in length. Mexico is bounded to the north by the United States (specifically, from west to east, by California, Arizona, New Mexico, and Texas), to the west and south by the Pacific Ocean, to the east by the Gulf of Mexico, and to the southeast by Belize, Guatemala, and the Caribbean Sea. The northernmost constituent of Latin America, it is the most populous Spanish-speaking country in the world. Mexico is the world's 13th largest country, three times the size of Texas.
Document 4: Mexico–United States border: The Mexico–United States border is an international border separating Mexico and the United States, extending from the Pacific Ocean to the west and Gulf of Mexico to the east. The border traverses a variety of terrains, ranging from major urban areas to uninhabitable deserts. s of 2010 , approximately 350 million legal crossings occur annually, and is the most frequently crossed border in the world.
Document 5: Paso del Norte International Bridge: The Paso del Norte International Bridge is an international bridge which crosses the Rio Grande (Río Bravo) connecting the United States-Mexico border cities of El Paso, Texas, and Ciudad Juárez, Chihuahua. The bridge is also known as "Paso del Norte Bridge", "Santa Fe Street Bridge", "Puente Benito Juárez", "Puente Paso del Norte" and "Puente Juárez-Santa Fe". The Paso del Norte International Bridge is a four-lane bridge for northbound non-commercial traffic only. The bridge was constructed in 1967. The American side of the bridge is owned and operated by the City of El Paso.
Document 6: Red River Canyon affair: The Red River Canyon affair, or the Battle of Red River Canyon, was a military action fought during the Taos Revolt of the Mexican-American War. Although the Americans mistakenly called this river by the name "Red", it was actually then and now more correctly called the Canadian River. On 26 May 1847, a detachment of American troops, traveling through northern New Mexico, were attacked by a combined force of Mexican militia with their Apache, Kiowa, and Comanche allies.
Document 7: United States Boundary Commissioner: Article V of the TREATY OF PEACE, FRIENDSHIP, LIMITS, AND SETTLEMENT BETWEEN THE UNITED STATES OF AMERICA AND THE UNITED MEXICAN STATES CONCLUDED AT GUADALUPE HIDALGO (known commonly as the Treaty of Guadalupe Hidalgo ) declared that the new boundary between the two republics of the United States and Mexico would lay "three leagues from land, opposite the mouth of the Rio Grande, otherwise called Rio Bravo del Norte, or Opposite the mouth of its deepest branch, if it should have more than one branch emptying directly into the sea; from thence up the middle of that river, following the deepest channel, where it has more than one, to the point where it strikes the southern boundary of New Mexico; thence, westwardly, along the whole southern boundary of New Mexico (which runs north of the town called Paso) to its western termination; thence, northward, along the western line of New Mexico, until it intersects the first branch of the river Gila; (or if it should not intersect any branch of that river, then to the point on the said line nearest to such branch, and thence in a direct line to the same); thence down the middle of the said branch and of the said river, until it empties into the Rio Colorado; thence across the Rio Colorado, following the division line between Upper and Lower California, to the Pacific Ocean. " It delineated the boundary through its text but wasn't written with much knowledge of the area's actually geography; A commissioner and surveyor from each country were appointed to precisely locate landmarks and accurately map the new border, relying on the treaty as their guide.
Document 8: Riverside Canal (El Paso): The Riverside Canal is an irrigation canal in El Paso County beginning southeast of El Paso, Texas. The canal acquires water from the Riverside Diversion Dam on the Rio Grande 15 mi southeast of El Paso. The canal is managed by the US Bureau of Reclamation. The canal extends for 17.2 mi with a capacity of 900 cubic feet per second. Water from the canal irrigates about 39,000 acres (160 km²). The canal and diversion dam is the southernmost system on an irrigation project extending along the Rio Grande in New Mexico and Texas. The canal supplies a canal network extending throughout the Upper Rio Grande Valley.
Document 9: 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 10: Canada–United States border: The Canada–United States border (French: "Frontière entre le Canada et les États-Unis"), officially known as the International Boundary, is the longest international border in the world between two countries. It is shared between Canada and the United States, the second- and fourth-largest countries by area, respectively. The terrestrial boundary (including portions of maritime boundaries in the Great Lakes, and on the Atlantic, Pacific, and Arctic coasts) is 8,891 km long, of which 2,475 km is Canada's border with Alaska. Eight Canadian provinces and territories (Yukon, British Columbia, Alberta, Saskatchewan, Manitoba, Ontario, Quebec, and New Brunswick), and thirteen U.S. states (Alaska, Washington, Idaho, Montana, North Dakota, Minnesota, Michigan, Ohio, Pennsylvania, New York, Vermont, New Hampshire, and Maine) are located along the border.
Document 11: List of companies of Mexico: Mexico is a federal republic in the southern half of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatemala, Belize, and the Caribbean Sea; and to the east by the Gulf of Mexico. Covering almost two million square kilometers (over 760,000 sq mi), Mexico is the sixth largest country in the Americas by total area and the 13th largest independent nation in the world. With an estimated population of over 127 million, it is the eleventh most populous country and the most populous Spanish-speaking country in the world while being the second most populous country in Latin America. Mexico is a federation comprising 31 states and a federal district that is also its capital and most populous city. Other metropolises include Guadalajara, Monterrey, Puebla, Toluca, Tijuana and León.
Document 12: Horcón Tract: The Horcón Tract is a small tract of land (a "banco") that, prior to 1905, was situated north of the Rio Grande in Texas. As the Rio Grande formed the international border, the tract was unambiguously American territory. In July 1906, however, the American Rio Grande Land and Irrigation Company dug a cutoff to shorten the course of the river, thus bypassing the tract. As a result, the 461 acre of the tract (including the former riverbed) became located south of the river. The company was eventually taken to court and fined for the diversion of the river, and the land was agreed to remain American territory, in accordance with the border treaty. In 1929 the town of Río Rico was founded near the tract on the Mexican side of the Rio Grande. As the Rio Grande changed its course after floods, the settlement was progressively pushed into the tract. The residents, being mostly of Mexican heritage, accepted the authority of the Mexican government and all parties generally acted as if the tract was Mexican territory. However, the United States never actually relinquished the land, and the issue was re-discovered decades later by a researcher. The Boundary Treaty of 1970 provided for the Horcón Tract to revert to Mexico upon the completion of two new flood control projects. Thus in 1977 the United States officially ceded the tract of land to Mexico. The Board of Immigration Appeals later determined that persons born in the Horcón Tract between 1906 and 1972 could not be deported, effectively if not technically granting citizenship. As a result, a large portion of the population of Rio Rico moved to the United States.
Document 13: Juan Cortina: Juan Nepomuceno Cortina Goseacochea (May 16, 1824 – October 30, 1894), also known by his nicknames Cheno Cortina, the Red Robber of the Rio Grande and the Rio Grande Robin Hood, was a Mexican rancher, politician, military leader, outlaw and folk hero. He was an important caudillo, military general and regional leader, who effectively controlled the Mexican state of Tamaulipas as governor. In borderlands history he is known for leading a paramilitary mounted Mexican Militia in the failed Cortina Wars. The "Wars" were raids targeting Anglo-American civilians whose settlement Cortina opposed near the several leagues of land granted to his wealthy family on both sides of the Rio Grande. Anglo families began immigrating to the Lower Rio Grande Valley after the Mexican Army was defeated by the Anglo-Mexican rebels of the Mexican State of Tejas, in the Texas Revolution. From 1836 to 1848 when Cortina was 12–24 years old, parts of the Cortina Grant North of the Rio Grande River was in the disputed territory between the Rio Grande and the Nueces Rivers, claimed by both Mexico and the Republic of Texas. The situation had a big impact on Cortina and his perspective on government and power. When the United States defeated Mexico in the Mexican-American War in 1848, Mexico was forced to concede the disputed territory to Texas. Cortina opposed this concession. However, Cortina's Mexican militia was easily defeated and forced to flee into Mexico when the Texas Rangers, the United States Army and the local militia of Brownsville, Texas and Matamoros, Tamaulipas. According to Robert Elman, author of "Badmen of the West", Cortina was the first "socially motivated border bandit," similar to Catarino Garza and Pancho Villa of later generations. His followers were known as the "Cortinistas."
Document 14: San Ysidro Port of Entry: The San Ysidro Port of Entry is the largest land border crossing between San Diego and Tijuana, and the busiest land border crossing in the world. It connects Mexican Federal Highway 1 with Interstate 5 on the U.S. side. The San Ysidro Port of Entry is one of three ports of entry in the San Diego–Tijuana metropolitan region.
Document 15: Chamizal dispute: The Chamizal dispute was a border conflict over about 600 acres on the Mexico–United States border between El Paso, Texas, and Ciudad Juárez, Chihuahua. It was caused by a shift in the Rio Grande, as a survey presented in 1852 marked differences between the bed of the Rio Grande (in Spanish: "Río Bravo del Norte" ) and the present channel of the river. The Chamizal was once the only link between El Paso and Ciudad Juárez and tensions over the territory during the historic Taft–Diaz summit almost resulted in the attempted assassination of both presidents on October 16, 1909.
ground_truth: approximately 350 million legal crossings