Nicaagat, also known as Chief, Captain and Ute Jack and Green Leaf. A Ute warrior and subchief, he led a Ute war party against the United States Army when it crossed Milk Creek onto the Ute reservation, which triggered the Battle of Milk Creek. Prior to the conflict, he had traveled to meet up with Major Thomas Tipton Thornburgh to learn of his intentions and warn him that crossing the Milk Creek onto the White River Ute reservation would be seen as an invasion and an act of war. When the army entered the reservation, a shooter from Nicaagat's band shot and killed Thornburgh.

Meeker Massacre, or Meeker Incident, White River War, Ute War, or the Ute Campaign), took place on September 29, 1879 in Colorado. Members of a band of Ute Indians attacked the Indian agency on their reservation, killing the Indian agent Nathan Meeker and his 10 male employees and taking five women and children as hostages. Meeker had been attempting to convert the Utes to Christianity, to make them farmers, and to prevent them from following their nomadic culture. On the same day as the massacre, United States Army forces were en route to the Agency from Fort Steele in Wyoming due to threats against Meeker. The Utes attacked U.S. troops led by Major Thomas T. Thornburgh at Milk Creek, 18 mi (29 km) north of present day Meeker, Colorado. They killed the major and 13 troops. Relief troops were called in and the Utes dispersed.