What is the official nickname of North Dakota?

Which state uses the postal abbreviation "ND"? Bismarck is the capital of which state? What is the largest city in North Dakota by population? In what year was North Dakota admitted to the Union as a state? What is the state bird of North Dakota? What is the state flower of North Dakota? What is the two-letter postal abbreviation for Ohio? Which state uses the postal abbreviation "OH"?