USA Official State Flag of South Dakota

South Dakota (SD) 

South Dakota state flag

The State Seal of South Dakota is centered on a sky blue field. The seal is surrounded by the rays of the sun. Encircling the seal and the sun are the words, "South Dakota" and "The Mount Rushmore State". 

If you want more information on the State Flags of the United States, you might want to check How Proudly They Wave: Flags of the Fifty States by Rita D. Haban. This book is geared toward kids... and for adults like me who want to know about the history and design significance of the flags of all fifty states but can't find this information in an expensive encyclopedia.