Full Description
Perhaps one of the most heartbreaking, yet subtly dangerous types of ghosts are the Crying Ones.  These are the restless spirits of children who died from neglect (starvation, lack of medical care, exposure, etc).  Unable to lie quietly in their graves, they rise every night, ceaselessly crying for comfort no one can give them.  
Though they are seldom seen, the tiny wraiths are a pitiful sight to behold.  They appear as pale, sickly, emaciated children dressed in pathetic rags.  They generally take no notice of their surroundings, but are usually observed as being huddled in a corner.  They are always sobbing.
These spirits are named for the noise of endless crying heard in their presence.  Generally, it is a low, wordless sobbing, although some have said that there are words to be heard, if one listens close enough.  (Generally things to the effect of “Please give me some food,” or “I’m so cold.”)  Though the Crying Ones are not malicious spirits, and, in fact, don’t even seem to register the presence of the living, they present a very real danger.  Listening to their crying for very long can plunge even the happiest of people into a deep depression that can lead to suicide or madness if left unattended to.  Not even the most heartless of people are immune to this.  The Crying Ones either don’t know or don’t care about the effect they have on people.  Mothers who love (or did love) their children fall into the depression much faster than others, and those who hate children much slower.  Other children are not immune, and may have nightmares caused by the presence of a Crying One.
Crying Ones generally haunt the place they died in, although there have been cases of them appearing in locations of great misery.  They are more likely to appear in places where there either are children or have been children in the past.  Orphanages (especially badly run ones) are particularly susceptible to being haunted by Crying Ones. 
The only known ways to lay these ghosts to rest are to either keep the child’s grave supplied with a large quantity of grave goods, particularly food, or for a “Matron spirit” to take care of them.  (Matron spirits are women who have devoted their lives to taking care of children, and devote their afterlives to taking care of the spirits of children.  They are understandably rare.)
Additional Information
Crying Ones are created through actual neglect from their parents or guardians.  A child who starved to death because his mother could not find enough food to keep him alive during a particularly bad winter would not arise as one, but a child who starved because no one bothered to feed him might.  No one is really sure about what causes a Crying One to rise; not all children who die from neglect become Crying Ones.  It is thought that the welfare of the one responsible for the child’s death has something to do with it.
Though they do not directly cause it, a place haunted by Crying Ones tends to accumulate ghosts of other types: the unhappy spirits of those who fell victim to the depression and madness caused by the endless crying.