This ham will be requested every year by your family. Be sure to get some Brennan's Cranberry Mustard for leftover ham sandwiches. The combo is delicious.
Position rack in bottom third of oven and preheat to 325F. Place ham on rack set in large roasting pan. Using sharp knife, score ham in diamond pattern. Press 1 clove in each diamond. Pour 4 cups water in roasting pan. Roast ham in 1 hour 30 minutes.
Meanwhile, blend marmalade, horseradish, and sugar in medium bowl.
Remove ham from oven. Transfer ham to baking sheet. Discard pan juices. Return ham to roasting pan. Add orange juice to roasting pan. Brush top of ham with 1/3 of marmalade glaze. Bake ham 10 minutes. Baste with orange juice in the pan, then brush with half the remaining glaze. Bake ham 10 minutes. Baste with orange juice in the pan and brush with remaining glaze. Roast ham until heated through, basting every 5 minutes, about 20 minutes longer. Let ham rest 15 minutes. Remove cloves. Transfer to platter. Serve ham hot, warm, or at room temperature.