In a small saucepan, combine sugar and water over medium heat. Heat until sugar dissolves into water and mixture is clear. Simmer for 1-2 minutes then remove from heat.
Add lemon juice, lemon zest, and whiskey to pan. Combine together then let mixture cool.
Pour mixture through a fine strainer into a large pitcher and mix
Add ginger ale, lemon slices and ice, then stir to combine. Enjoy!