In humans, T cells differentiate in thymus and B cells develop in bone marrow (BM), but the natural killer (NK) precursor cell(s) and site(s) of NK development are unclear. The CD56^bright NK subset predominates in lymph nodes (LN) and produces abundant cytokines compared to the cytolytic CD56^dim NK cell that predominates in blood. Here, we identify a novel CD34^dimCD45RA(+) hematopoietic precursor cell (HPC) that is integrin α₄β₇^bright. CD34^dimCD45RA(+)β₇^bright HPCs constitute <1% of BM CD34(+) HPCs and ∼6% of blood CD34(+) HPCs, but >95% of LN CD34(+) HPCs. They reside in the parafollicular T cell regions of LN with CD56^bright NK cells, and when stimulated by IL-15, IL-2, or activated LN T cells, they become CD56^bright NK cells. The data identify a new NK precursor and support a model of human NK development in which BM-derived CD34^dimCD45RA(+)β₇^bright HPCs reside in LN where endogenous cytokines drive their differentiation to CD56^bright NK cells in vivo.