Westward ho! If you travel across certain parts of the United States, you can still see wagon wheel ruts where people crossed the west in search of more opportunity and better lives more than 200 years ago! The Oregon Trail: The Journey Across the Country from Lewis and Clark to the Transcontinental Railroad offers readers ages 9 to 12 a fascinating look at the explorers and settlers who traveled this route during the westward expansion of the United States.