Freshwater is a precious commodity for mankind, and irrigation is one of the largest component of freshwater usage by mankind. Many uncertainties exist in determining the amount of freshwater usage for irrigation. This manuscript discusses various ways to quantify irrigation and application of remote sensing to assess irrigation fluxes. With future, high-resolution remote sensing platforms becoming available, this work will be helpful to develop application pertaining to irrigation quantification especially is drought affected and semi-arid regions of the world.