For thousands of years, millions of monarch butterflies have migrated from the northern U.S. and Canada to Mexico for the winter. But exactly how they know where to go is still a mystery.

Monarchs traveled to a remote part of Mexico, a journey they've made for thousands of years, and wintered there. Now tens of millions of the butterflies are on an epic aerial journey back north.

Sightings of monarch butterflies have been seen predominantly near southern cities like Savannah and St. Mary's, according to Journey North's interactive migration map ... reported the eastern ...

The peak of the spring monarch butterfly migration in Texas typically occurs from late March to early April. See where on Journey North.

Sightings of monarch butterflies have been seen predominantly near southern cities like Savannah and St. Mary's, according to Journey North's interactive migration map. Here's what we know ...