It looks like it might be here: +44° 29' 20.92", -73° 14' 58.38". I've tried climbing it before, the start is awfully wet though...
Thanks for the super accurate (I think) response. I was only about 1000ft from this during my last trip to Burlington, and didn't even realize it. I might have to take a look at it the next time I'm nearby. How deep was the water? Does the water around Burlington stay pretty chilly year round?
Juniper Island (44.449468,-73.279166) looks like it also has some good potential on the west side, but since it's privately owned (according to wikipedia) I doubt there's any possibility of that happening.
J Miles, the only way to access that boulder is to hike on the trail running down the coast of the lake, which can be accessed from the northern most point of north beach towards "Lone Rock Point". The water is frigid until about June, and is most comfortable in August/September. The boulder is about 50ft from shore and the water is at least 12ft deep (couldn't reach the bottom). I climbed around the backside (V0 but dangerous fall potential onto a smaller rock) and jumped off safely.
In case you are looking for other places, the more well known DWS area in Burlington is along the shoreline of Red Rocks Park.