Often the main official presence in smaller localities (where the post office is often found in a corner of the general store, operated by the storekeeper). Moves are afoot to staff rural post offices with trained clerks-minor, reporting to the Gryphon Clerks, and also tasked with educating the children and any adults who want to learn.
The Post Office Acts stipulate that nobody who is not in the service of the realm and properly licenced may carry a pressure weapon, a knife longer than their forearm including the handle, a bow or crossbow, or a polearm or spear, other than in a locked case, within 3072 dwarfpaces of a post office. Since they also stipulate that post offices must be no more than 2560 dwarfpaces apart in populated areas, this effectively means that weapons are banned in towns and cities. In the more rural areas, this law tends to get ignored as long as nobody does anything stupid.
The symbol of the Post Office is a stylized horse. Blue triangles set into the road point towards the nearest one in most cities and large towns.