I know there are a lot of political realists and liberal theorists on this board. I am not an anarchist, but a problem you'd find with an "Anarcho-communist" "country" is that no other country is going to be anarcho-communist but that "country" (and the whole point of anarch-communism is no state, but I get what you mean). For the purposes of discussion, I'll just refer to it as an anarcho-communist society.
This region would likely be faced by a number of problems. Notwithstanding all sorts of issues with the actual theory itself, in terms of international relations if you're placing this in the post-1900s, but pre-1950s-ish a lot of states are totalitarian and expansionist. It's a lot harder for an anarcho-communist society to get a trustworthy milita capable of defending against hostile attacks. For a society like this to function, you need to basically isolate it from the rest of the world imo. The problem is, few places in the world that are isolated have the means to support large populations. At best, in my opinion- without writing a whole damn essay on it, you're going to get an odd state the size of Luxembourgh in a place like the Himalayan Mountains, obscure islands in Melanesia or Micronesia or a far northern commune in Canada or far southern commune in Argentina. This society is likely to not be a "state", but simply an incorporated commune in territory claimed (perhaps even administered) by another state.
A region like this is also highly likely to see integration into a global capitalist market at some point. There are plenty of societies that are isolated and largely "anarchic" in nature (Mormons for instance). Not "anarchism" by any means, but don't participate in government, largely self-sufficient, communal, tend to have more de-centralized hierarchy (it's still there though). However they see a fair turnover every year of people wanting to leave and live elsewhere. In this anarcho-comunist society, I'd expect the same sort of thing to happen.