Mayville is a village in Chautauqua County, New York, United States.
 The population was 1,709 at the 2010 census, which is down 2.7% from the 2000 census.
 Mayville is in the town of Chautauqua and is the county seat of Chautauqua County.
 The village and town offices share a building on Main Street, directly across from the Chautauqua County courthouse.
Tallgrass Beef Company is a Kansas-based beef company that sells grass fed and grass finished beef.
 Tallgrass Beef became the first grass fed beef producer to sell steaks in Chicago in 2005 when Harry Caray’s Restaurant began selling Tallgrass Beef.
 Its beef is sold via restaurants and grocery stores throughout the Midwest, East Coast, and Southeast, in addition to mail order.
 Tallgrass Beef Company raises some of its cattle on founder Bill Kurtis's Sedan, Kansas ranch.
 Tallgrass also has a network of family farmers and ranchers who raise and finish grass fed cattle that fit the standards of the Tallgrass protocols.
Elgin is a city in Chautauqua County, Kansas, United States, on the state line with Oklahoma.
 As of the 2010 census, the city population was 89.
 The south edge of the city is the Kansas-Oklahoma state border.
Chautauqua is a city in Chautauqua County, Kansas, United States.
 As of the 2010 census, the city population was 111.
Peru is a city in Chautauqua County, Kansas, United States.
 As of the 2010 census, the city population was 139.
Chautauqua County (county code CQ) is a county located in Southeast Kansas.
 As of the 2010 census, the county population was 3,669.
 Its county seat and most populous city is Sedan.
 Chautauqua County is named for Chautauqua County, New York, the birthplace of Edward Jaquins, a Kansas politician who was instrumental in getting the county established.
Sedan is the county seat of and the largest city in Chautauqua County, Kansas, United States.
 As of the 2010 census, the city population was 1,124.
Hewins is a small unincorporated community in Chautauqua County, Kansas, United States.
 The post office was established April 4, 1906, and closed April 8, 1966.
 Hewins was named after Edwin M. Hewins, a rancher and member of the Kansas Legislature.
Chautauqua County is the westernmost county in the U.S. state of New York.
 As of the 2010 census, the population was 134,905.
 Its county seat is Mayville, and its largest city is Jamestown.
 Its name is believed to be the lone surviving remnant of the Erie language, a tongue lost in the Beaver Wars; its meaning is unknown and a subject of speculation.
 The county was created in 1808 and organized in 1811.
Jamestown is a city in southern Chautauqua County, New York, in the United States.
 The population was 31,146 at the 2010 census.
 Situated between Lake Erie to the northwest and the Allegheny National Forest to the south, Jamestown is the largest population center in the county.
 Nearby Chautauqua Lake is a freshwater resource used by fishermen, boaters and naturalists.

Question: What is known as the county seat of and the largest city in Chautauqua County, Kansas, United States?
Answer: Sedan, Kansas