This war was fought between the Netherlands and the Isle of Scilly, which is located off the southwest coast of Great Britain. The war started in 1651, but like many wars of that era it was not taken seriously and soon forgotten about. Three centuries passed before the two countries finally agreed to a peace treaty in 1986, making their war the longest in human history.
War duration: (1651-1986) Three hundred and thirty-five years.
Casualties: None.