Peel and finely shred carrots using a box grater or a food processor fitted with a shredding disc.
In a large mixing bowl, whisk together the mayonnaise, sugar, lemon juice, and salt until the dressing is smooth and the sugar has dissolved.
Add the shredded carrots and raisins to the bowl with the dressing.
Fold the ingredients together until the carrots and raisins are evenly coated with the dressing.
Cover the bowl and refrigerate for at least 30 minutes before serving to allow the flavors to integrate and the raisins to soften slightly.