Fossiliferous sediments of the Hadar Formation (Afar, Ethiopia) are preserved in the Hadar, Dikika, Gona, and Ledi-Geraru research areas, and have produced the most informative record of the mid-Pliocene hominin Australopithecus afarensis. Hundreds of specimens of A. afarensis have been recovered from the Hadar site, including a partial skeleton (A.L. 288–1), two nearly complete adult skulls (A.L. 444–2; A.L. 822–1), and a dense accumulation of hominin individuals of various ages (A.L. 333; Johanson et al., 1978b; Kimbel et al., 1994; Kimbel and Delezene, 2009). Across the Awash River at Dikika, a juvenile hominin skeleton (DIK-1–1) was recovered and possible evidence of hominin carnivory ~3.4 Ma based on cut-marked bone was reported from Hadar Formation sediments (Alemseged et al., 2006; McPherron et al., 2010; Thompson et al., 2015). Thus, the outcrops of the Hadar Formation, particularly those at Hadar, have been tremendously important in interpreting Pliocene hominin evolution in eastern Africa.