Complex sentence: On August 17,2009, Bill was honored by the City of Rapid City and the State of South Dakota, which declared September 2,2009, as William M. Groethe Day in honor of the 61st anniversary of the Little Bighorn photo.
Split into simpler sentences: On August 17,2009, Bill was honored by the City of Rapid City and the State of South Dakota. Both entities declared September 2,2009, as William M. Groethe Day, in honor of the 61st anniversary of the Little Bighorn photo.