I would suggest checking out new camps around the start of next year, and applications start around mid-January of each year. Also start to think about what type of residential camp you want to work at-- private, non for profit, boy/girl scout, YMCA, special needs etc.
For camp jobs you can check websites such as campstaff.com and what I did, was also search for camps on the aca website, and I used the one that was for parents looking for camps for their kids, because when I was using the camp jobs listing there were very little available postings, but when I contacted camps that were accredited with the ACA, they said they did have job openings, and they did not know that posting a job on the ACA website was an option.
