The Missouri River once flowed northeasterly through this valley to Hudson Bay, but during the Bull Lake Ice Age an ice dam near Loma diverted the river into its current channel. That channel began filling with glacial sediment, preventing the river from returning to its original course when the dam finally broke about 70,000 to 130,000 years ago. Several sections of the highway between Loma and Havre follow Big Sandy Creek in the old river channel. From this point there is a panoramic view of the drainages of three major Montana river systems, the Teton, Marias, and Missouri. To the southwest, the Teton and Marias Rivers merge near Loma before joining the Missouri River about a mile downstream. In the background are the Bear's Paw Mountains to the east, Square Butte and Round Butte to the southeast, the Highwood Mountains toward the south, and the Little Belt Mountains in the southwest. Because of the geography, this area became a crossroads for many events important to Montana history, including the passage of the Lewis and Clark Expedition in 1805, followed by fur traders, the steamboat, the Great Northern Railway, and homesteaders.