Question: The Darlington Agency was a stop on the trail that had a northern post in what state?
Related documents: [0]  [DOC] The Darlington Agency was an Indian agency on the Cheyenne and Arapaho Indian Reservation in Canadian County, Oklahoma. The agency was established in 1870, when the agency established at Fort Supply the previous year was moved to a more accessible location for the tribes. Brindon Darlington, a Quaker for whom the agency was named, was the first agent at the agency, a position he held until his death in 1872. The agency gained a post office and an Indian school run by John Homer Seger, and it became a stop on the Chisholm Trail. By 1880, the agency had its own newspaper, the "Cheyenne Transporter"; it was the first in western Oklahoma. The Cheyenne left to form their own agency at Concho in 1897; when the Arapaho reunited with them, they both occupied the Concho agency, and the Darlington Agency became the property of the State of Oklahoma. The Masons used the site for a boarding school and retirement home until 1922; the state then briefly used the site as a drug rehabilitation center before making it the Oklahoma Department of Wildlife Conservation's main bird hatchery and research station. [END] 
[1]  [DOC] The Chisholm Trail was a trail used in the post-Civil War era to drive cattle overland, from ranches in Texas to Kansas railheads. The portion of the trail marked by Jesse Chisholm went from his southern trading post near the Red River, to his northern trading post near Kansas City, Kansas. [END] 
Answer: 
Kansas
Kansas