Combine cherries, sugar, and water in a saucepan; bring to a boil, stirring occasionally.
Continue to cook over medium-high heat for 20 minutes.
Reduce to a simmer and cover, cooking on low heat for 10 minutes, or until soft.
Remove from heat and strain over a bowl using a fine mesh strainer to mash the cherry juice from the cherries.
Let syrup cool at room temperature.
Seal into an airtight jar and store for up to 2 weeks.