Question: The county that includes Buena Vista borders what what county?

full_context: Document 1: Warner Cope: Born in Kentucky, Cope came to California in 1850 and tried mining, but found little success. In 1853 he resumed work as an attorney, first in El Dorado County and the next year in Jackson, Amador County. In October 1858, he was elected to the California State Assembly from Amador as a Democrat.
Document 2: Albert City, Iowa: Albert City is a city in Buena Vista County, Iowa, United States. The population was 699 at the 2010 census.
Document 3: Buckhorn, Amador County, California: Buckhorn is a census-designated place in Amador County, California. Buckhorn sits at an elevation of 3,238 feet (987 m). The community is in ZIP code 95666 and area code 209. The 2010 United States census reported Buckhorn's population was 2,429.
Document 4: Scottsville, California: Scottsville is an unincorporated community in Amador County, California. It is southeast of Jackson. It lies at an elevation of 1270 feet (387 m).
Document 5: Robert C. Kirkwood: Robert C. Kirkwood (August 30, 1909 – May 5, 1964) served as a member of the California State Assembly representing part of Santa Clara County from 1947 until 1953, when he resigned to accept an appointment as California State Controller by Governor Earl Warren. Kirkwood was elected to a full term in 1954, but lost a re-election bid in 1958 to Alan Cranston, who later became a United States Senator.
Document 6: Bernard Coy: Coy was a native of Kentucky who turned to crime during the Great Depression and, in 1937, was sentenced to 25 years imprisonment. He was transferred to Alcatraz from Atlanta in 1938 and was later given the position of cell-house orderly which allowed him access through most of the main cell-block on Alcatraz. This relative freedom allowed him to spot a tiny flaw in one of the prison's security features, the bars of the gun-gallery overlooking the cell house. Coy along with Joe Cretzer, Marvin Hubbard, Sam Shockley, Miran Thompson, and Clarence Carnes planned to break into the gun galleries to steal weapons, take hostages and then flee to the dock. He was successful in creating a makeshift bar-spreader that enabled him to get through the relatively weak bars that protected the gun galleries and overpower the unsuspecting guard on his return from investigating a fabricated incident caused by Shockley in the prison's secure unit, D-Block.
Document 7: Pine Grove, Amador County, California: Pine Grove is a census-designated place in Amador County, California. It lies at an elevation of 2513 feet (766 m). The population was 2,219 at the 2010 census. It is located at , along State Route 88. The community is in ZIP code 95665 and area code 209.
Document 8: David C. Westenhaver: Born in Berkeley County, West Virginia, Westenhaver received a Bachelor of Laws from Georgetown Law in 1886. He was in private practice in Martinsburg, West Virginia from 1886 to 1903, serving as a prosecuting attorney of Berkeley County from 1886 to 1887, and as a member of the Martinsburg City Council from 1902 to 1903. He then moved his practice to Cleveland, Ohio from 1903 to 1917, and was a member of the Board of Education of Cleveland from 1912 to 1915.
Document 9: Vista Robles, California: Vista Robles, formerly Hearst, is an unincorporated community in Butte County, California. It lies at an elevation of 141 feet (43 m). The name Hearst is in honor of George Hearst, an early settler.
Document 10: Southern California: Subsequently, Californios (dissatisfied with inequitable taxes and land laws) and pro-slavery southerners in the lightly populated "Cow Counties" of southern California attempted three times in the 1850s to achieve a separate statehood or territorial status separate from Northern California. The last attempt, the Pico Act of 1859, was passed by the California State Legislature and signed by the State governor John B. Weller. It was approved overwhelmingly by nearly 75% of voters in the proposed Territory of Colorado. This territory was to include all the counties up to the then much larger Tulare County (that included what is now Kings, most of Kern, and part of Inyo counties) and San Luis Obispo County. The proposal was sent to Washington, D.C. with a strong advocate in Senator Milton Latham. However, the secession crisis following the election of Abraham Lincoln in 1860 led to the proposal never coming to a vote.
Document 11: Pete Goicoechea: Goicoechea was born in Salt Lake City and studied at Utah State University. He has owned a ranch since 1970 and also worked for many years for the Eureka County, Nevada road department. He served on the Eureka County Commission from 1987 to 2002 and then was elected to the Nevada State Assembly. He has also served as a member of the Nevada State Land Use Planning Advisory Council, the Nevada Grazing Board, and he has been the Director of the Nevada Water Resource Association. He is affiliated with the Eureka Volunteer Fire Department, E Clampus Vitus, the Humboldt River Authority, and the Nevada Rural Health Center. Goicoechea is a Catholic. He and his wife Glady are the parents of two children.
Document 12: Charles P. Snyder: After studying law, he was admitted to the bar and opened a practice. He became prosecuting attorney of Kanawha County and served from 1876 to 1884. He was elected in 1882 to the Forty-eighth Congress to fill the vacancy caused by the resignation of John E. Kenna He won re-election to the Forty-ninth and Fiftieth Congresses and served from May 15, 1883 to March 3, 1889. He served as a judge on the criminal court of Kanawha County from 1890 to 1896. He was named United States consul to Ciudad Porfirio Diaz, Mexico from 1897 to 1901. He died in Vineland, New Jersey in Cumberland County on August 21, 1915 and was buried in Spring Hill Cemetery in Charleston, West Virginia.
Document 13: Buena Vista, Amador County, California: Buena Vista (formerly, The Corners) is a census-designated place in Amador County, California. It lies at an elevation of 295 feet (90 m). It is located south-southeast of Ione, at . The community is in ZIP code 95640 and area code 209. The population was 429 at the 2010 census.
Document 14: Chinatown, Amador County, California: Chinatown is a former settlement in Amador County, California. It is situated at an elevation of 344 feet (105 m).
Document 15: Arroyo Vista, California: Arroyo Vista is an unincorporated community in El Dorado County, California. It lies at an elevation of 974 feet (297 m).
ground_truth: El Dorado County
sub_queries: Buena Vista >> located in the administrative territorial entity Answer: Amador County
Amador County >> shares border with Answer: El Dorado County