Letterboxing Glossary: U
A letterbox with a status of unknown means that the owner of the box isn't sure if the letterbox is available to find or not. They probably received reports about it possibly being missing but have yet to check on it themselves to confirm or deny the letterbox's demise.
- urban letterbox
A letterbox hidden in a city or town instead of the traditional areas such as forests or parks. They usually require a little more creativity to hide since they tend to be in very public area and are frequently microboxes which make them easier to hide. You'll want to be especially careful looking for urban boxes since you don't want to draw attention to yourself or the letterbox, nor alarm anyone because you are acting 'suspiciously'.