Question: A tintype image of White Hair can be see at a museum in a city that is the county seat of what county?
Context: The Cerro Gordo County Courthouse is located in Mason City, Iowa, United States.  When Cerro Gordo County was created in 1855 and Mason City was selected to be the county seat.  Dissatisfaction in the western part of the county led the Iowa legislature to appoint three new commissioners who would move the county seat to Livonia.  A courthouse was built there.  A petition signed by over half of the citizens of the county requested that the county seat be moved back to Mason City.  Mason City also won the election in 1858 to decide the matter 155-48.  Two courthouses have stood in Mason City prior to the present Modernist structure that was occupied by the county in 1960.  It had been built as the Standard Oil Building, and was acquired by the county in 1959 for $159,400 and then remodeled for their use. Mason is a city in the U.S. state of Michigan.  It is named after the state's first governor, Stevens T. Mason.  As of the 2010 census, the city population was 8,252.  It is the county seat of Ingham County.  Mason is the only city in the U.S. that serves as a county seat ahead of a state capital, with the capital of Lansing also in Ingham County.  Despite Mason being the county seat, many county offices and courtrooms are located in Lansing. Ellicott City is an unincorporated community and census-designated place, along with being the county seat of local government in Howard County, Maryland, United States.  It is part of the Baltimore Metropolitan Area.  The population was 65,834 at the 2010 census.  Founded in 1772, the town contains the B. & O. Railroad Museum's branch at the Ellicott City Station, built in 1830 as the first terminus of the initial line.  The downtown historic district is located in the valley of the small Tiber River, with its east end abutting the Patapsco River, which forms the Baltimore County line.  As of the 2000 census, Ellicott City surpassed Towson (county seat of neighboring Baltimore County) for the first time, as the largest unincorporated county seat in the country. The Former Audubon County Courthouse, also known as the Audubon County Historical Society Museum, is a historic building located in Exira, Iowa, United States.  Court proceedings were first held in a schoolhouse in Hamlin’s Grove after Audubon County was established in 1851.  The county seat was relocated to Exira ten years later, and a disagreement erupted over where the county seat should be located.  The county board of supervisors made an appropriation for a new courthouse in 1871, but its construction was delayed due to the disagreement.  Exira eventually won and officials constructed the courthouse for about $2,200.  The Exira Hall Company was established to build the two-story, frame structure.  County offices were located on the first floor and the courtroom was located on the second floor.  The county seat was moved to Audubon in 1879. The Allen County Museum is located in the city of Lima, the county seat of Allen County, Ohio, United States.  Occupying a half city block, the museum campus includes the main museum building, a log house, the MacDonell House (a Victorian mansion), a Shay Locomotive display, Military/Transportation building, the Children's Museum, and the Children's Garden.  The museum is accredited by the American Alliance of Museums.  According to recent reports of the American Alliance of Museums Accreditation Department, less than 800 museums, out of more than 11,000 in the United States, are accredited.  Standards for accreditation apply across the board to both small and large institutions. Van Buren is a city that is the county seat of Carter County, Missouri, in the United States.  It is the largest town in Carter County.  Van Buren was founded in 1833 as the county seat of Ripley County and was named after then Vice President of the United States, Martin Van Buren.  In 1859 Van Buren became a part of the newly created Carter County and was subsequently selected to be the county seat.  The 2010 U.S. Census shows Van Buren with a population of 819, a decrease of 3.1 percent from its 2000 population of 845. The Croquet Tintype is an alleged tintype image of Billy the Kid and the Lincoln County Regulators purportedly taken in September 1878.  If real it is the only known photo of Billy the Kid and the Regulators together and the only image to feature their wives and female companions. The Johnston Library is a historic library located at 210 W. 10th St. in Baxter Springs, Kansas.  The building was constructed in 1872 to serve as a courthouse during Baxter Springs' unsuccessful attempt to become the Cherokee County seat.  Though Baxter Springs had lost an election to choose the county seat in 1869 to Columbus, supporters of both cities had attempted to fraudulently swing the election in their favor, and Baxter Springs hoped it could still become county seat in the future.  The building initially served as the county jail and sheriff's office until Columbus completed its jail in 1880.  After this, Baxter Springs ultimately gave up its attempts to become the county seat, and the building became its city hall.  In 1905, resident Niles P. Johnston bequeathed $5,000 to the city to start a library, and the city hall building was chosen to house it. Pawhuska is a city in and the county seat of Osage County, Oklahoma, United States. White Hair (Pawhuska) is the English name of several Osage leaders in the eighteenth and nineteenth century.  A tintype image of White Hair can be seen at the Osage Nation Museum in Pawhuska, Oklahoma.
Answer: Osage County