The mandatory vaccination order includes day and overnight camps.
Parents must provide documentation that their child has received two doses of the MMR vaccine.
Only medical exemptions, supported by a medical professional, will be accepted.
There have been 255 measles cases confirmed in Rockland since the outbreak began last October.
The CDC said last week that the nation’s measles crisis has reached a level not seen in a generation, with nearly 1,000 cases reported this year.
Most of those have been centered in the New York area and Orthodox Jewish communities.