Complex sentence: The St. Vrain massacre (although not a by the correct definition of the word) was an event during the Black Hawk War that occurred near present-day Pearl City, Illinois in Kellogg's Grove on May 24,1832.
Split into simpler sentences: The St. Vrain massacre (although not a by the correct definition of the word) was an incident in the Black Hawk War. It occurred near present-day Pearl City, Illinois in Kellogg's Grove on May 24,1832.