Irf8 Delta32 mice have a CRISPR targetted deletion in the enhancer of the mouse Irf8 gene located at +32 kilobases from the Irf8 gene promoter. This deletion removes the binding site for the Jun/Batf3/Irf8 complex and results in a complete and permanent elimination of the development of the cDC1 lineage of dendritic cells, more complete than the old Batf3-knockout mice. The lineage does not come back under conditions that allow cDC1 to re-develop in Batf3-KO mice, and should be useful in studies such as in mTb infection and others.