The lockdowns began at 12:45 p.m. while police investigate the call to the high school's main office, Schools Supt. C. Lauren Schoen said in an email to parents.
The call was deemed non-credible and the lockdowns were lifted at 1:38 p.m., Schoen said.
"A police presence will remain on Ridge Road for the remainder of the school day," the superintendent said. "We thank the Mahwah Police Department for [its] continued support in maintaining a safe learning environment for our students."
Click here to follow Daily Voice Parsippany-Troy Hills and receive free news updates.