For 8 years now, we've maintained a list of local R user groups here at the Revolutions blog. This is a list that began with a single group (the Bay Area RUG, the first and still one of the largest groups), and now includes 360 user groups worldwide (including 27 specifically for women).
As the list has grown in size, it's become harder to manage. Thankfully, Colin Gillespie of Jumping Rivers Consulting has risen to the task, by creating a new website based on a GitHub repository that anyone can contribute to. I've updaed the Local R User Group Directory to point to these new pages, specifically the lists of:
If you have a group of your own, contributing to the list is easy. All you need is a GitHub account, and you can click the Edit button to edit one of the R Markdown pages directly. If you're not familiar with R Markdown, you can also suggest an edit via the Issues page.
(Incidentally, It would be great to automate the process of generating a count and a map of local R user groups. If anyone wants to take up the challenge of writing an R script to process the Rmd pages, please do!)
As R grows in popularity, it's awesome to see local communities get together and form these groups. If you'd like to start one yourself, here are some tips on starting up a local user group.