Cinnamon does keep snakes away because snakes hate the smell of Cinnamon.
But you can deter the snakes even better by using Clove Oil along with the Cinnamon.
Take 1 oz of Cinnamon and 1 oz of Clove oil and mix it together in a spray bottle and then spray the areas where the snakes are hanging out.
The Snakes Will hate the smell and will avoid those areas so you won't see them again.
You may have to spray the area every few days to keep the scent strong enough so the snakes will be deterred.
You can also sprinkle some cinnamon around the area and put some clove around the area as well and mix it with the cinnamon which does a better job at deterring the snakes than just the cinnamon.