The Imperial Gallon is a unit of measurement for liquid volume that is primarily used in the United Kingdom and some Commonwealth countries. It is defined as equal to 4.54609 liters, which is larger than the U.S. gallon, which is approximately 3.78541 liters. The Imperial Gallon is often used for measuring fuel and other liquids. This measurement originated from the British Imperial System, which was established in the 19th century. The Imperial Gallon is divided into four quarts, each of which contains two pints. Understanding this unit is important for conversions and comparisons with other volume measurements, such as the U.S. gallon.