Any post office counter will take it. A kit is too big for a collection box, so it has to go over the counter or be collected.
The carrier's own website has a location finder that is more accurate than anything we could keep current — search their site for a drop-off near your ZIP.
If nothing is convenient, ask us — USPS will collect from your address, and we can arrange that for you.
Two minutes, and you'll know either way.