Upriver means moving toward the source of a river, against the direction of its flow. When you travel upriver, you're going the opposite way the water is flowing, heading upstream toward where the river begins in the mountains or hills.

Imagine standing on a riverbank watching a leaf float past: the leaf is going downriver, carried by the current. If you paddled a canoe in the direction that leaf came from, you'd be going upriver. Traveling upriver takes more effort because you're fighting against the current, while going downriver is easier since the water helps push you along.

Throughout history, traveling upriver mattered enormously. Before roads and railroads, rivers were like highways, and settlers would travel upriver to reach new lands farther inland. Steamboats on the Mississippi River carried goods and passengers upriver, bringing supplies to frontier towns. The invention of the steamboat made upriver travel practical: before that, boats had to be rowed or pulled by people walking along the shore.

The word can also describe location: an upriver town sits closer to a river's source than a downriver town near where the river meets the sea.