What would cause honda accord rattling noise from rear?

It's not uncommon to hear a rattling noise from the rear of Your Honda Accord, but the reasons run the gamut and can be close to anything. Funny story, I had a persistent rattle in my old Accord that turned out to be a pair of Vise Grips that I left while replacing a rear strut. Unrelated, but wouldn't it be funny Anyway, much more likely than Vise Grips, You're probably looking at a failed or failing suspension component, though it's difficult to rule out something simple like a loose trunk latch. Specifically, degraded ball joints or failing struts will cause a rattle, as will faulty sway bar links. That's likely where You should start with Your diagnostics, and feel free to give us an update if You were (or weren't!) able to find the cause.