* Rapunzel: This princess is perhaps the most famous for her long, magical hair, which is used by a witch to climb up to her tower.
* Snow White: While not as incredibly long as Rapunzel's, Snow White is also known for her beautiful, dark hair.
* The Little Mermaid: While not strictly a princess, Ariel's long, flowing red hair is iconic.
* Sleeping Beauty: In some adaptations, Sleeping Beauty is depicted with very long, flowing hair.
Do you have any more clues about the princess you're thinking of? Perhaps the color of her hair, the story she's from, or any other details? This could help me narrow down the possibilities!