Place a medium saucepan over medium-high heat. Add the water, sugar, and ground cinnamon. Stir to combine. Cook until the sugar is dissolved. Remove from heat and set aside.
To a 1 1/2 gallon punch bowl add the pumpkin, apple cider, orange juice, seltzer, lemon juice, spiced rum, and vodka. Whisk to combine. (Use a whisk, it helps break up the pumpkin puree.) Pour in the cinnamon simple syrup and stir once more.
Add lemon slices and a few cinnamon sticks to the punch bowl.
For Serving:
Portion the punch into glasses and garnish with a cinnamon stick.
Notes
This punch is also delish without any alcohol.
Recipe makes about 1 gallon of punch = 16 8-ounce servings