Welcome to the Dunham Washington Park Memorial Cemetery! While some are still just barely legible, many of the stone grave plots in this cemetery have long since been weathered away. However what is most interesting is that the majority of them date between the 1750s-1850s.
The first thing you might notice about this odd little locale is its place in a residential neighborhood. It unfortunately seems that the township merely built around it without putting in the proper time and effort to preserve these important artifacts of Edison’s history.
During colonial times, much of the southern part of Edison was part of Piscataway Township. This is where the name of the nearby Piscatawaytown Burial Ground comes from. Moreover, you will find many Dunhams in this cemetery from this loosely defined Piscataway region. Here is some information I was able to retrieve about the Dunham family who this cemetery appears to be named after, and who appear to have been one of the first European families to settle in the area:
The Dunhams, of Piscataway, (for there was a different lineage of same name at Woodbridge), had as their progenitor a worthy sire in the person of Benjah Dunham. Their family tradition asserts that he settled in this vicinity several years previous to its formal occupation by any other Englishmen. His first child born was Edmund, whose birth in 1661 was the earliest of any white child born in the township. Edmund Dunham grew to be an influential member of society, and became a lay preacher, helping to mould the tender consciences and direct the religiously inclined of the pioneer community. In 1681 he married Mary, or Elizabeth Bonham, a member of another early planter's family. Their son, Jonathan, in after years, succeeded his father in the ministry of the Seventh-Day Baptist Church, of Piscataway, of which the father may be said to be the founder in 1705-7. (http://www.anamericanfamilyhistory.com/Bonham%20Family/BonhamMaryDunham.html)
Here is a link to some additional information that has been gathered about the individual graves: https://www.findagrave.com/cemetery/2193786/memorial-search?page=1#sr-16407004
The cache itself should be an easy find on the edges of the cemetery. Your best bet is approaching it off of Baldwin Road. Muggles should not be much of an issue, but be wary of the occasional neighbor peeking at you from their windows. Lastly, bring your own pen and HAVE FUN :)