I now have the underlying peer-reviewed study (via the LJMU university repository) plus the Denver Museum of Nature & Science's own research pages and the journal publisher's release. Here's my fact-check. VERDICT: TRUE The viral claim is supported by the primary scientific record, with one small wording caveat: researchers describe the trackmaker as *"likely"/"most likely"* an adult T. rex (based on footprint size, tridactyl shape, age, locality, and the abundance of T. rex bones nearby), rather than stating it as a proven certainty. **Claim-linked findings** - **The trackway is real, is a *sequence* (not a single print), and is attributed to an adult T. rex.** The peer-reviewed paper — Falkingham, Hups, Tamez-Galvan, Bercovici & Lyson (2026), *Journal of Vertebrate Paleontology*, DOI 10.1080/02724634.2026.2706201 — describes an ~7 m (23 ft) trackway of four large tridactyl tracks, each ~1 m long, from the Upper Cretaceous Hell Creek Formation of North Dakota, dated ~66.5 Ma, and states it "marks the first report of a trackway that is likely attributable to an adult *Tyrannosaurus rex*" ([LJMU Research Online record of the paper](https://researchonline.ljmu.ac.uk/id/eprint/29394/)). - **The location matches the claim: North Dakota.** The discovery was made in 2025 on federal land administered by the U.S. Forest Service near Marmarth, in southwestern North Dakota's Hell Creek Formation, and the museum states that "while isolated footprints have been attributed to adult T. rex in the past, this is the first time scientists have described a sequence of tracks, or trackway, likely left by this most famous of dinosaurs" ([Denver Museum of Nature & Science press release](https://www.dmns.org/press-room/press-releases/denver-museum-of-nature-science-discovers-first-ever-adult-t-rex-trackway/); [DMNS T. rex Trackway research page](https://www.dmns.org/science/research/t-rex-trackway/)). **Two independent primary sources** 1. Peer-reviewed study (university repository hosting the accepted manuscript + abstract + DOI): [researchonline.ljmu.ac.uk/id/eprint/29394](https://researchonline.ljmu.ac.uk/id/eprint/29394/) — Liverpool John Moores University, *Journal of Vertebrate Paleontology*, 2026. 2. Research institution's own release/pages: [dmns.org press release](https://www.dmns.org/press-room/press-releases/denver-museum-of-nature-science-discovers-first-ever-adult-t-rex-trackway/) and [dmns.org/science/research/t-rex-trackway](https://www.dmns.org/science/research/t-rex-trackway/) — Denver Museum of Nature & Science. (Publisher-side confirmation: [Taylor & Francis Newsroom](https://newsroom.taylorandfrancisgroup.com/first-ever-trackway-of-adult-t-rex-discovered/), 9 Sept 2026.) **Caveats / precision** - The attribution is probabilistic: the paper's title says "*likely* attributable," and the museum says T. rex is "the most likely trackmaker" — the track surfaces are heavily weathered and "retain little anatomical detail beyond size and number of digits" ([LJMU record](https://researchonline.ljmu.ac.uk/id/eprint/29394/)). - "First ever" refers specifically to a **trackway (sequence)**; isolated prints had previously been attributed to adult T. rex ([DMNS press release](https://www.dmns.org/press-room/press-releases/denver-museum-of-nature-science-discovers-first-ever-adult-t-rex-trackway/)). - Study details: four prints (two left, two right), stride ~13 ft, estimated walking speed ~3.5–4.5 mph (1.5–2 m/s), found by teacher Kent M. Hups; published 8 Sept 2026 ([DMNS research page](https://www.dmns.org/science/research/t-rex-trackway/)). Bottom line: the TikTok claim is **true as stated in substance** — the first known *trackway* attributed to an adult *Tyrannosaurus rex* was indeed discovered in North Dakota — though the scientific sources frame the trackmaker identification as "most likely" rather than definitive.