Tamiahua Lagoon (Spanish: Laguna de Tamiahua) is a long coastal lagoon in the Mexican state of Veracruz. It is an inlet of the Gulf of Mexico that extends 65 miles south from Tampico. The peninsula of Cape Rojo separates the lagoon from the sea. The islands of Idolo and Juana Ramírez lie within the lagoon. The settlements of Tamiahua and lie along its shores.