Root hairs develop from the region of

The entire root is covered with the epidermis, a single layer of closely packed cells that often have thin projections known as root hairs. In roots, the root hairs arise from the zone of maturation. This is a differentiated zone bearing root hairs.

The root tip contains the root apical meristem. Above the root tip, there is a multicellular root cap. Behind the root apical meristem, there is a zone of elongation.