Back in 2009 I developed a haunted formula to judge how likely a location is to be haunted. There were certain characteristics that were in common in the 50 very reportedly haunted locations.
Those items included:
History of deaths (49 of 50 study's sites had this)
Death and trauma at the location in its history
Nearby waterway (41 of 50 study's sites had this)
This involves moving water
Masonry or brick construction (43 of 47 study's sites had this - 3 locations weren't counted as they were not constructions)
Wood frame buildings were least haunted, but the exception was being located in a mining town.
Over 50 years old (50 of 50 study's sites met this criteria)
(incidentally found the majority of the 50 sites studied were near a railroad track - an often haunted location in forests and fields)
Geology (top 4 geologic contents listed from most common first)
With this formula, I could be called to a new possibly haunted location and get a sense of how many of these elements were there and the likelihood of haunting.
If you want to encounter a ghost, I'd suggest the top 5 locations to run into one.
Gettysburg Battlefield, Pennsylvania
Trans-Allegheny Lunatic Asylum, Kentucky
LaLaurie Mansion, Louisiana
St. Augustine Light Station, Florida
Ohio State Reformatory, Ohio
There are a variety of features that these 5 above locations have that make them great targets. As well, they offer a variety of settings for a haunting to take place as well as greatly documented encounters on a regular basis.
Should you be searching for a location to have an encounter, keep in mind some of the common characteristics listed above.