Geography and Migration
Why Do Monarchs Hug the Atlantic Coast?

This map shows three great places to watch monarch migration on the Atlantic Coast. Wind, geography, and monarch behavior combine to make them good spots.

Monarchs use the wind to migrate. East winds carry monarchs toward Mexico. But westerly winds can carry them the wrong way. When butterflies reach the Atlantic Coast they can't go any farther safely. Trapped by open water, they must travel southward along the coastline.

Look closely at the three sites labeled on this map. Next, look below the map to see why each is an especially good place to watch monarch migration.

Google Maps


1) Cape May, NJ
Cape May is at the southern tip of New Jersey. Every fall, large concentrations of butterflies come through on their way to Mexico. Monarchs gather at Cape May until conditions are right. They must cross the Delaware Bay — 13 miles of open water — to continue their journey.

2) Assateague, VA
Next they follow the coastline south. On Virginia's Assateague Island they find Chincoteague National Wildlife Refuge. This conserved land provides important habitat where monarchs can rest and refuel.

3) Cape Charles, VA
Further south, Cape Charles is another natural funnel where monarchs concentrate before crossing open water again.

Migration Research Explores Questions

  • How quickly do monarchs travel down the Atlantic Coast?
  • Do monarchs ever get carried away by the wind?
  • Do monarchs ever make it to Mexico from here?

Some of these questions are being answered by researchers Dick Walton at Cape May and Denise Gibbs at Assateague.