Bring a large pot of salted water to a boil. Add the dry macaroni noodles and cook according to package instructions.

Drain the noodles in a colander and rinse under cold water to cool them down.

In a mixing bowl, combine the cooled macaroni, diced corned beef, cubed Swiss cheese, well-drained sauerkraut, and diced dill pickles.

In a separate bowl, whisk together the Thousand Island dressing, mayonnaise, Dijon mustard, and sauerkraut brine if using.

Pour the dressing mixture over the pasta and other ingredients. Stir gently until everything is coated.

Cover the bowl and chill in the refrigerator for at least 1 hour.