Place cut potatoes in a large pot and fill with water until the potatoes are covered by water by at least an inch. Add the salt, cover, and bring to a boil.
Once potatoes are boiling, reduce heat and simmer for 7-8 minutes until the potatoes are tender. Drain and rinse with cold water to stop them from cooking further.
While the potatoes are cooking, prepare the rosemary dressing. Combined all the ingredients in a large mixing bowl. Add celery and cooked potatoes. Fold them into the dressing until evenly coated. Taste and adjust seasonings if needed.
Place in the fridge for at least 15 minutes (although I recommend a few hours) to allow the flavors to combine before serving. Serve chilled. Leftovers will keep in the fridge for 5 days.