When searching Issues/Pull Requests there is no filter to search through closed milestones.
Here is a screenshot of setting a milestone when opening an issue, and it has the closed milestones tab, which should be added to filtering for issues and PRs.
Hi @BrennanConroy ,
Thanks for this feedback! We're always working to improve GitHub and the GitHub Community Forum, and we consider every suggestion we receive. I've logged your feature request in our internal feature request list. Though I can't guarantee anything or share a timeline for this, I can tell you that it's been shared with the appropriate teams for consideration.