A region between to river is called Doab. For example the Doab designates the flat alluvial tract between the Ganga and Yamuna rivers extending from the Shivalik hills to the two rivers confluence at Allahabad.
During British period Doab was divided into three administrative districts-
1- Upper Doab - Meerut
2- Middle Doab - Agra
3- Lower Doab - Allahabad