2011 Spring break in U.S.

when?

[smallcompany]

When is the Spring 2011 elementary school break in U.S.?
I guess it varies by states or school districts, but wonder if there's any majority that has it at the same time.
We may go to Disneyland, Universal Studios, Zoo in San Diego, Great Canyon and more during the last two weeks of March, and I'm trying to put Disneyland into the time frame when there's less people around.

Thanks

[weeks]

You're right, it floats like Easter does. As early as mid-March or as late as mid-April.