* The name is slightly different: Could you be thinking of a school with a similar name? Perhaps a slight misspelling?
* It's a smaller, less known school: The school might be very local and not have a large online presence.
* It's a private school: Private schools often have less readily available information online than public schools.
If you can provide more information, such as the city or state it's located in, I might be able to help you find it.