How many state names in the U.S. start with the letter "O"?

There are three state names in the United States that start with the letter "O". They are Ohio, Oklahoma and Oregon. Ohio is a state in the mid-western region of the United States. It is the 34th largest by area, the 7th most populous, and the 10th most densely populated state in the country. The state's capital and largest city is Columbus. Ohio is known for its status as both a swing state and a bellwether in national elections. Six Presidents of the United States have been elected who had Ohio as their home state. Oklahoma is a state located in the South Central part of the United States. It is the 20th most extensive and the 28th most populous state of the 50 United States. The state's name is derived from the Choctaw words okla and humma, meaning "red people". It is also known informally by its nickname, The Sooner State. It became the 46th state to enter the union. The third state on the list is Oregon. It is a state in the Pacific Northwest region of the United States. Oregon is bordered on the west by the Pacific Ocean, on the north by Washington, on the south by California, on the east by Idaho, and on the southeast by Nevada. It is the ninth largest and, with a population of 4 million, 26th most populous state in U.S. It was admitted into the union as the 33rd state in February 1859.