[KyleGoetz]

I made reference to my 新漢英字典, and it gives a usage note that, in regards to river names, 川 is a suffix particularly for Japanese rivers, whereas 河 is used more for non-Japanese rivers.

For example, アマゾン河 (Amazon River, in S. America) vs. 江戸川 (Edo River, in Kanto).

There were also many words that use one or the other. Presumably, these are fixed usages.

I'm thinking of this dichotomy like that of 聴く・聞く, where the meaning is slightly different, but no one's going to kill you for the ever-so-slight mistake. A Japanese person want to chime in on this?