Hey there, stlwick,
Thanks so much for using Apple Support Communities.
Was this event from a calendar that you signed up for intentionally or is it something you don't recognize, perhaps a spam type calendar event? If it's the latter, we want to share some information which can help get rid of those types of events and calendars. You can follow the steps here for that: Delete spam calendars and events on iPhone - Apple Support
However, if it's simply a normal event that you want to delete, you could follow the steps here instead to delete that event via iCloud on the web: Delete or hide a calendar event on iCloud.com - Apple Support.
If you're using a Mac or iOS device, you could follow these articles instead:
We hope that this information is helpful.
Have a great day!