Question: What county shares a border with another county, in which the town of Polk is located?

full_context: Document 1: Colgate, Wisconsin: Colgate is an unincorporated community in Washington County, Wisconsin, United States, straddling the county line with Waukesha County. Colgate is located partially in the village of Richfield, and the town of Lisbon. Its ZIP code is 53017.
Document 2: Milltown, Wisconsin: Milltown is a village in Polk County, Wisconsin, United States. The population was 917 at the 2010 census. The village is located within the Town of Milltown.
Document 3: West Bend (town), Wisconsin: West Bend is a town in Washington County, Wisconsin, United States. The population was 4,834 at the 2000 census. The City of West Bend is located partially within the town. The unincorporated community of Nabob is located in the town.
Document 4: Otsego, Wisconsin: Otsego is a town in Columbia County, Wisconsin, United States. The population was 757 at the 2000 census. The unincorporated community of Otsego is located in the town. The villages of Rio and Doylestown lie in the geographic area of the town of Otsego.
Document 5: Polk, Wisconsin: Polk is a town in Washington County, Wisconsin, United States. The population was 3,938 at the 2000 census. The unincorporated communities of Ackerville, Cedar Creek, Cedar Lake, Diefenbach Corners, Mayfield, and Rugby Junction are located in the town. The town derives its name from James K. Polk, 11th U.S. President, who was in office when Wisconsin attained statehood in 1848.
Document 6: Washington County, Wisconsin: According to the U.S. Census Bureau, the county has a total area of 436 square miles (1,130 km2), of which 431 square miles (1,120 km2) is land and 5.0 square miles (13 km2) (1.2%) is water. It is the fifth-smallest county in Wisconsin by total area.
Document 7: Plat, Wisconsin: Plat was an unincorporated community and is now a neighborhood in the village of Richfield, Washington County, Wisconsin, United States. It is located at the intersection of Plat Road and Monches Road. It is 2 miles from the towns of Erin and Merton and from County Trunk Highway Q (County Line Road) and the Waukesha County and Washington County division.
Document 8: Jackson (village), Wisconsin: Jackson is a village in Washington County, Wisconsin, United States. The population was 6,753 at the 2010 census. The village is adjacent to the Town of Jackson.
Document 9: Westford, Richland County, Wisconsin: Westford is a town in Richland County, Wisconsin, United States. The population was 594 at the 2000 census. The unincorporated communities of Bunker Hill and Germantown are located in the town. The unincorporated community of Corwin was also located in the town.
Document 10: Grant County, Wisconsin: Grant County comprises the Platteville, WI Micropolitan Statistical Area. It is in the tri-state area of Illinois, Iowa, and Wisconsin, and is crossed by travelers commuting to Madison from a number of eastern Iowan cities, and by residents of northern Illinois traveling to the Twin Cities or La Crosse, Wisconsin.
Document 11: Sarah Childress Polk: Sarah Polk ("née" Childress; September 4, 1803 – August 14, 1891) was the First Lady of the United States from 1845 to 1849. She was the wife of the 11th President of the United States, James K. Polk.
Document 12: Richfield, Washington County, Wisconsin: Richfield is a village in Washington County, Wisconsin, United States. The population was 11,300 at the 2010 census. The unincorporated communities of Colgate and Hubertus are located partially in Richfield.
Document 13: Wayne, Washington County, Wisconsin: Wayne is a town in Washington County, Wisconsin, United States. The population was 1,727 at the 2000 census. The unincorporated communities of Kohlsville and Wayne are located in the town.
Document 14: Polk, Illinois: Polk is an unincorporated community in Will County, Illinois, United States. It lies just north of the Kankakee County line and south of Beecher.
Document 15: Peck, Wisconsin: Peck is a town in Langlade County, Wisconsin, United States. The population was 354 at the 2000 census. The unincorporated community of Ormsby is located in the town. The town was named in honor of George Wilbur Peck who served as the 17th governor of Wisconsin from 1891-1895.
ground_truth: Waukesha County
sub_queries: Polk >> located in the administrative territorial entity Answer: Washington County
Washington County >> shares border with Answer: Waukesha County