Myrtle Beach, South Carolina, USA
Moaning Myrtle, character in the HarryPotter series. She is a ghost who was killed by the basilisk that resides in Salzaar Slytherin's Secret Chamber.
Myrtle Wilson, from "The Great Gatsby"
Myrtle the turtle, the biggest turtle in Boston's aquarium
Myrtle Fargate, character from American ABC soap "All My Children"