Merrimac may refer to:

• Merrimac, Queensland, Australia
  • Electoral district of Merrimac

• Merrimac, California
• Merrimac, Illinois
• Merrimac, Kentucky
• Merrimac, Massachusetts, the original town with the name "Merrimac"
• Merrimac, Virginia
• Merrimac, Mingo County, West Virginia
• Merrimac (town), Wisconsin, a town
• Merrimac, Wisconsin, a village
• Merrimack River, in Massachusetts and New Hampshire, of which Merrimac is an earlier spelling

• Merrimac coup
• USS Merrimack, several, some spelled "Merrimac"
• Merrimack (disambiguation)
• Meramec (disambiguation)