Question: Which county shares a border with the county where Mahaska is located?

full_context: Document 1: Lanham, Kansas and Nebraska: Lanham is an unincorporated community in both Washington County, Kansas and Gage County, Nebraska in the United States. It is located along State Line Road just west of K-148/Nebraska Highway 112. Its main street forms the state line.
Document 2: Muscotah, Kansas: Muscotah is a city in Atchison County, Kansas, United States. As of the 2010 census, the city population was 176. Muscotah was named for the Kickapoo Native American word for "prairie"
Document 3: Mahaska, Kansas: Mahaska is a city in Washington County, Kansas, United States. As of the 2010 census, the city population was 83.
Document 4: Blaine, Kansas: Blaine is an unincorporated community in Pottawatomie County, Kansas, United States. It is located 29 miles northeast of Manhattan at the crossroads of K-99 and K-16.
Document 5: Barnes, Kansas: Barnes is a city in Washington County, Kansas, United States. As of the 2010 census, the city population was 159.
Document 6: Stateline Township, Sherman County, Kansas: Stateline Township is one of the thirteen townships of Sherman County, Kansas, United States. The population was 344 at the 2000 census.
Document 7: Lanham, Maryland: Lanham is an unincorporated community and census-designated place in Prince George's County, Maryland. As of the 2010 United States Census it had a population of 10,157. The New Carrollton station (the terminus of the Washington Metro's Orange Line) as well as an Amtrak station are across the Capital Beltway in New Carrollton, Maryland. Doctors Community Hospital is located in Lanham.
Document 8: Geographic center of the United States: Its position as located in a 1918 survey is located at 39 ° 50 ′ N 98 ° 35 ′ W ﻿ / ﻿ 39.833 ° N 98.583 ° W ﻿ / 39.833; - 98.583 ﻿ (Geographic Center of the Contiguous United States), about 2.6 miles (4.2 km) northwest of the center of Lebanon, Kansas, approximately 12 miles (19 km) south of the Kansas - Nebraska border.
Document 9: Palmer, Kansas: Palmer is a city in Washington County, Kansas, United States. As of the 2010 census, the city population was 111.
Document 10: Circle of latitude: 40 ° N In the USA, the border between Nebraska and Kansas. The parallel was originally chosen for the Mason -- Dixon line, but the line was moved several miles south to avoid bisecting the city of Philadelphia.
Document 11: Washington, Kansas: Washington is a city in, and the county seat of, Washington County, Kansas, United States. As of the 2010 census, the city population was 1,131.
Document 12: Washington Township, Harlan County, Nebraska: Washington Township is one of sixteen townships in Harlan County, Nebraska, United States. The population was 66 at the 2000 census. A 2006 estimate placed the township's population at 61.
Document 13: Linn, Kansas: Linn is a city in Washington County, Kansas, United States. As of the 2010 census, the city population was 410.
Document 14: K-8 (Kansas highway): K-8 is the name of two separate state highways in Kansas, United States. The southern highway is a road, linking Oklahoma State Highway 8 (SH-8) to the town of Kiowa. The northern highway links U.S. Route 36 (US-36) near Athol to Nebraska Highway 10 (N-10) near the town of Franklin.
Document 15: Hanover, Kansas: Hanover is a city in Washington County, Kansas, United States. As of the 2010 census, the city population was 682; as of 2014, it was estimated to have decreased to 665. It is the second most populous town within Washington County.
ground_truth: Gage County
sub_queries: Mahaska >> located in the administrative territorial entity Answer: Washington County
Washington County >> shares border with Answer: Gage County