Upriver means in the direction a river comes from — away from the sea, towards the source, against the flow. It works as an adverb ('we walked upriver'), as an adjective before a noun ('the upriver villages'), and sometimes loosely as a place ('he lives upriver'). Its opposite is downriver. A learner's mistake is to think it means north. It has nothing to do with the compass; it only means against the current. If a river runs north, then upriver is south. There is also a feeling attached to it in English writing. Because roads and cities usually follow the lower part of a river, 'upriver' often suggests somewhere smaller, older, more remote — the quiet place further in. Upstream means the same thing physically and is the more common word overall, but upstream also has a wide business use (upstream in the supply chain) that upriver never has.