Mills reservation is a 45' vertical traprock cliff .Only a few routes but worth a look if your in the area.Top rope setup with gear or very long slings.Short moderate climbs between 5.5 and 5.10 .Nice small area for locals.The climbs are easily identified by name : Left Ceiling(5.9)Left Corner(5.8)Left Face(5.7)Center Crack(5.5)Right Face(5.10)
There is some bouldering in the north end of the park.Some of the taller problems could be top roped .
The area is in in view of houses so be courtious to neighbors and respect private property.
This can be protected a number of ways. First off, this is leadable, especially the center crack.
For toproping, this is where I started my first setups when I began climbing. I bought a 50 foot static line, which was sufficient to connect to two trees. A tad longer might be appropriate but you can certainly make it work. The trees are hardy even if they weren't the thickest. You can also protect it WC 4 Friend or 3 BD Camalot at the top. You can get creative with some nuts and tricams as well as well as some smaller cams above the ledge overlooking the climb (top ledge near walking path). If you have a decent rack and are comfortable with anchors you can make plenty work here.
I checked this place out for the first time today, great little local crag. Easy to set up a a top rope anchor with a decent rack, or if you have a lot of static line. It seems as though there used to be a better trail that went from the main trail that runs below the cliff up to the belay spot, but it has now become very overgrown and could use some maintenance. Spring project???
Does anyone know if climbing is really permitted there? I'm not any sort of lawyer or attorney, but I've never heard that it's legal to do roped climbing there. Nor have I heard that it's illegal.
The NJ Rock Climbing printed guidebook said they didn't know either. Their advice was to back off and go away if anyone questioned whether you should be climbing there -- not get into a confrontation, not try to assert that you have a "right" to climb. (There was another rock along the same ridge in northern NJ that got explicitly closed)
From a safety perspective, I'd say the Mills rock is one of the better candidates in northern NJ for trying to get explicit permitted status for roped climbing -- if somebody wanted to work toward that, like with advice from the Access Fund.
But meanwhile seems to me it makes sense to keep it low-key, not offend the neighbors with noise or litter, not offend other park users (mainly local folks who want to stop in for a quick walk with their dog) by holding prime Parking spaces for hours (which shouldn't be a problem if use the Google Maps location given here above, and hike up the hill from the east, which is also the shortest).
My feeling is that while the Mills rock does have some worthwhile moves for experienced outdoor climbers, it is not a fun introduction to outdoor rock for indoor gym climbers. Because the holds near the ground are sort of strange and slopy, often hard to find from below, lots of feeling around. Especially the obvious "main crack".
There's so few NJ gym climbers nowadays who get outdoors at all, so if one of them wants to try, better not to humiliate them in their first moves just getting off the ground their first time. Much better bet is to take them to the Gunks.
Also my opinion is that the numerical difficulty ratings in the NJ Climbing guidebook (and so far shown here on MountainProject) are "local sandbags" typical of little crags everywhere -- expect at least one grade tougher than the Gunks (which are themselves tougher than mainstream USA Yosemite grades).
Top-roping? Be aware that although the top of the rock is not on one of the marked hiking trails, it's still fairly obvious, and popular becausee it has a nice view over the valley to New York City. So it's not unusual for people to walk along the top, and some of them could fiddle with your anchor gear, or toss something down.