I used to work for the Y in their summer camps. I would recommend staying far away.

I don't know if this will be helpful or not, but right now I'm taking a gymnastics class that is designed for 1-3 year olds through the Arlington YMCA. I've been SERIOUSLY disappointed. The class is "taught" by what seems to be two high schooler or college girls. There is pretty much zero interaction with the kids. Of course the parents are there, but I've been to lots of other classes and the teachers at least try to have some sort of schedule. This is basically open play.
However, I did inquire about doing a makeup class, and it seems that all of the other classes are taught by a "real" teacher. She seems to be really legit, though I haven't seen how she interacts with the kids.
So, this isn't a camp, but I've not been impressed with the Y so far, and I wouldn't do another class through them.

The Arlington YMCA has a camp program that I'm interested in for my six year old. However, we live in DC and it would be an extra hike, so I was hoping to get some feedback on whether the YMCA in Arlington has a good reputation for summer camps. Is it safe? Do they keep the kids active and interested? Is there enough senior staff that I don't have to worry that I'm leaving my child with a bunch of distracted, texting teenagers who will yell to keep order? Thanks! (and yes, I'm calling them too)