This also varies from camp to camp. If you're a camp counsellor, you can expect to be responsible for 6 to 12 campers at any one time. You may have a co-counsellor, who also helps you with this group.
If you're an activity specialist, this will vary depending on the activity you work on. For example, a land sports specialist may find themselves with up to 20 campers, but a woodworking specialist would likely supervise a much smaller group.
We recommend connecting with your camp directly to see what group sizes you can expect to find in your cabin or at your activity, and this will help you plan your activities accordingly!