The Arkansas River through central Arkansas long served as a major travel and trade route before roads were built, though its shifting sandy bottom and currents made it dangerous to navigate. Bernard de La Harpe, the first European known to explore the Arkansas River, arrived here in 1722 on a French expedition to determine whether the area was suitable for colonization and to map the river and its tributaries. La Harpe and 25 men traveled upstream from Arkansas Post to a point 50 miles from Little Rock near Petit Jean Mountain, and knowledge gained during this expedition opened the way for many hunters and traders to use the river as their main route. La Harpe's journal recorded the hazards of the journey, including a small pirogue being dashed against a log by the force of the current, overturning and losing tools, weapons, wheat, and clothes before the party pulled the boat free and continued. The McClellan-Kerr River Navigation System later transformed the river with locks and dams, flood control measures, and a maintained channel, making it safer to navigate today.