Mason is a city in southwestern Warren County, Ohio, United States, approximately 22 miles from downtown Cincinnati. As of the 2010 census, Mason's population was 30,712. Mason has experienced fast growth, with its historic Main Street remaining at the center of the community. Mason went from being a sleepy farm town of less than 5,000 residents in the 1960's to a large bustling community of Cincinnati commuters in the 1990's.

Mason is home to the Kings Island Amusement Park, and one of the largest tennis stadiums in the world, the Lindner Family Tennis Center, home of the Western & Southern Open.

On June 1, 1803, Revolutionary War veteran William Mason paid $1,700 at auction to purchase 640 acres (2.6 km²) of land in what is now downtown Mason. In 1815, he platted 16 lots on this land and named the village "Palmira." In 1832, two years after the death of William Mason and according to his will, more than 40 additional lots were platted on the north, south, and west of Palmira. When the plat was officially recorded, the name of the village was listed as "Palmyra."

Ohio (ⁱ/oʊˈhaɪ.oʊ/) is a state in the Midwestern United States. Ohio is the 34th most extensive, the 7th most populous, and the 10th most densely populated of the 50 United States. The state's capital and largest city is Columbus.

The name "Ohio" originated from Iroquois word ohi-yo’, meaning "great river". The state, originally partitioned from the Northwest Territory, was admitted to the Union as the 17th state (and the first under the Northwest Ordinance) on March 1, 1803. Although there are conflicting narratives regarding the origin of the nickname, Ohio is historically known as the "Buckeye State" (relating to the Ohio buckeye tree) and Ohioans are also known as "Buckeyes".

The government of Ohio is composed of the executive branch, led by the Governor; the legislative branch, which comprises the Ohio General Assembly; and the judicial branch, which is led by the Supreme Court. Currently, Ohio occupies 18 seats in the United States House of Representatives. Ohio is known for its status as both a swing state and a bellwether in national elections.