Opinion of the Court
uments, and preserves—including the Yukon–Charley Preserve—and expanded three old ones. See §§410hh, 410hh–1. In line with the Park Service’s usual terminology, ANILCA calls each such park or other area a “conservation system unit.” §3102(4) (“The term… means any unit in Alaska of the National Park System”); see 54 U. S. C. §100102(6) (similar).
In sketching those units’ boundary lines, Congress made an uncommon choice—to follow “topographic or natural features,” rather than enclose only federally owned lands. §3103(b); see Brief for Respondents 24 (agreeing that “ANILCA [is] atypical in [this] respect”). In most parks outside Alaska, boundaries surround mainly federal property holdings. “[E]arly national parks were carved out of a larger public domain, in which virtually all land” was federally owned. Sax, Helpless Giants: The National Parks and the Regulation of Private Lands, 75 Mich. L. Rev. 239, 263 (1976); see Dept. of Interior, Nat. Park Serv., Statistical Abstract 87 (2017) (Table 9) (noting that only 2 of Yellowstone’s 2.2 million acres are in non-federal hands). And even in more recently established parks, Congress has used gerrymandered borders to exclude most non-federal land. See Sax, Buying Scenery, 1980 Duke L. J. 709, 712, and n. 12. But Congress had no real way to do that in Alaska. Its prior cessions of property to the State and Alaska Natives had created a “confusing patchwork of ownership” all but impossible to draw one’s way around. C. Naske & H. Slotnick, Alaska: A History 317 (3d ed. 2011). What’s more, an Alaskan Senator noted, the United States might want to reacquire state or Native holdings in the same “natural areas” as reserved federal land; that could occur most handily if Congress drew boundaries, “wherever possible, to encompass” those holdings and authorized the Secretary to buy whatever lay inside. 126 Cong. Rec. 21882 (1980) (remarks of Sen. Stevens). The upshot was a vast set of so-called inhold-
