On February 2, the Indians left their large camp on the South Platte River and continued north toward the Powder River country of Wyoming to join their relatives there. The Sioux led the way as they were most familiar with the territory. En route the Indians had two more skirmishes in Nebraska with the U.S. army at Mud Springs and Rush Creek. In subsequent months, the Indians frequently raided wagon trains and military establishments along the Oregon Trail in Wyoming. In the summer of 1865, the Indians launched a large-scale offensive in the Battle of Platte Bridge (present-day Casper, Wyoming) achieving a minor victory. Later that summer, the U.S. army invaded Indian territory in Wyoming with more than 2,000 soldiers in the ineffective Powder River Expedition.