My great grandfather was a John Roycroft who migrated to the US in the 1800s. His progeny settled in Baltimore, MD. I have found several John Roycrofts in the Census data from Cork. They were taken in the 1700s.There are a number of Roycrofts living today in Schull, Skibbereen and other hamlets in western County of Cork. You should be able to find a telephone directory which lists all of them.