We won't spoil anything here if you haven't watched the film yet, but it's a pretty pivotal scene near the end of the film. Originally the site of a Christian monastery over a thousand years ago, Skellig Michael was a perfect fit for Star Wars based on its look, a location that felt alien and grounded at the same time. In this video from Discover Ireland, we get a little behind the scenes on this location and why J.J. Abrams and the team decided it would work for the film:

It will be interesting to see how much more we'll get to see of this island in future films. There have been some reports that the production won't be returning for future movies due to environmental reasons (in addition it's a UNESCO World Heritage site), but we have no official word yet. If you'd like to learn more about Skellig Michael and Little Skellig, he's a terrific video that goes into greater detail about the islands and the ecosystem, which has quite a bird population:

It's important as an industry that we consider our impact on a place before we shoot, especially if we're filming somewhere that's a piece of history. It's difficult to bring a whole film crew and not have any sort of impact on a location, so I'm sure that's something the filmmakers and Ireland considered for future filming there.

Source: Discover Ireland