Hematopoiesis varies in distinct skeletal sites. Bone marrow was isolated from mouse calvaria, long bones, and vertebrae, and the proportions of hematopoietic populations were identified by flow cytometry. The proportion of HSPCs (A), myeloid progenitors (B), B-lymphocyte populations (C), erythroid populations (D), granulocytes (E), and macrophages (F) varied by skeletal site. All data are mean ± SD, pooled from 3 independent experiments (n = 7 to 9 mice per cell type). One-way ANOVA with Tukey’s multiple comparisons test: *P < .05; **P < .01; ***P < .001; ****P < .0001. C, calvaria; GMP, granulocyte-macrophage progenitor; L, long bones; MkP, megakaryocyte progenitor; Pre GM, pregranulocyte-macrophage progenitor; Pre MegE, premegakaryocyte/erythroid progenitor; V, vertebrae.