Where do horseshoe crabs spawn on sandy beaches?

Horseshoe crabs are marine arthropods that come ashore to breed on sandy beaches and shallow coastal flats. In North America, they are especially associated with the Atlantic coast, from the Gulf of Mexico region north to New England, with major spawning beaches in places like Delaware Bay. They also occur in parts of Asia, where different species use coastal habitats to reproduce. Females lay eggs in the sand, and large spawning events can attract birds that feed on the eggs. Despite their name, horseshoe crabs are more closely related to spiders than to true crabs.