Long story short: there was a guy named Nathan Hofheimer who had a copper mine in Warren, NJ. When the copper mine gave up all the copper it could, Hofheimer filled it with water and surrounded it with a semi-circular, multi-level structure made from rocks pulled from the mine, creating the impressive and eponymously named, Hofheimer Grotto. More info about the copper mine on Mindat.org.
The Grotto is currently the property of Elks Lodge 885. It’s open to the public and can be found at 99 Bardy Rd, Warren, NJ, nestled in the woods on the Elks Lodge property.
Sadly, the Grotto has fallen into disrepair. People throw tires, shopping carts, picnic tables, and every kind of trash you can imagine into the Grotto orifice — masks, vape cartridges, dental floss picks, blue bags filled with canine excrement, beer bottles, pizza boxes, Monster energy drink cans — it’s all in there. On top of the garbage, the Grotto is overgrown with all manner of weeds, including the thick-trunked Tree of Heaven (Ailanthus altissima), which attract the lousy Spotted Lantern Flies that parasitize them. The water in the Grotto is stagnated and green. It doesn’t smell bad though, which is good.
Regardless of the decay, the Hofheimer Grotto is worth checking out. I climbed its Roman coliseum-like structure and chilled for about 30 minutes. Greeted dog-walkers as they entered the park. It was nice.
South-east of the Grotto, you’ll find the Hofheimer Cemetery. I found the Mausoleum, which was totally desecrated, slathered with spray paint, and had a collapsed roof. I walked the nearby trails and saw some mounds that looked human-body-sized.
So what can be done?
I’ve read that part of the problem is getting power to the Grotto to power lights and a fountain to keep the water from stagnating. Allegedly, Warren Township and the Elks need to cooperate on this, and they can’t agree on a path forward. Maybe, solar to make everyone happy? Then get a team of volunteers from the Lodge, a wood-chipper, chainsaws, and a dumpster, and get rid of the brush. Pump put the water. Fix or put in the fountain. Put in some lights. Rainbow LED fountain lights. Make it safe for families. Fix up the cemetery. I’m willing to help.