The flag of the state of South Dakota represents the U.S. state of South Dakota with a field of sky blue charged with a version (in navy blue on white) of the state seal in the center, surrounded by gold triangles representing the sun's rays, surrounded in turn by inscriptions in gold sans-serif capitals of "SOUTH DAKOTA" on top and "THE MOUNT RUSHMORE STATE" (the state nickname) on the bottom. The inscription on the bottom was "THE SUNSHINE STATE" before it was changed in 1992.
The official pledge of the South Dakota flag is "I pledge loyalty and support to the flag and state of South Dakota, land of sunshine, land of infinite variety." The only protocol to the state flag pledge is that it does not either replace or preempt the Pledge of Allegiance to the flag of the United States.
The original flag of South Dakota consisted of a dominant sun encircled by the text "South Dakota" and "The Sunshine State". The 1909 statute stated:
The Flag of South Dakota shall consist of a field of blue, one and two-thirds as long as it is wide, in the center of which shall be a blazing sun in gold, two-fifths as wide in diameter as the width of the flag. Above this sun shall be arranged in the arc of the circle, in gold letters, the words 'South Dakota' and below this sun in the arc of the circle shall be arranged the words in gold letters, 'The Sunshine State', and on the reverse of the blazing sun shall be printed in dark blue the Great Seal of the State Of South Dakota. The edges of the flag shall be trimmed with a fringe of gold, to be in proportion to the width of the flag. The staff shall be surmounted by a spearhead to which shall be attached cord and tassels of suitable length and size.