Broken Arrow was a region in the western part of the Confederation of Vandalia that bordered the Mexican state of Mexico del Norte. Silver was discovered in the region in 1844, attracting miners from both Mexico and the Confederation of North America. The border between the two nations was then uncharted, and both laid claim to an area of 5 million acres (7800 square miles) in the Broken Arrow region. By 1845, fighting between Mexican and North American settlers had broken out in the area. From February to June, 156 Mexican and 197 North Americans were killed, and the towns of Morelos and Kinsey were destroyed in the fighting. The fighting in the Broken Arrow region led to the outbreak of the Rocky Mountain War.