In a large bowl, mix the thawed shrimp, diced red onion, and celery. Stir gently to distribute the ingredients evenly.

In a separate bowl, whisk together the mayonnaise, lemon juice, Old Bay seasoning, dill, and half of the kosher salt. Adjust with remaining salt and black pepper.

Pour the creamy dressing over the shrimp mixture, and gently fold until well coated.

Serve immediately for the freshest taste, or store in an airtight container in the refrigerator for up to four days.