Troodon fossil map
Where fossils of Troodon have been found, shown on the Earth as it looked about 75 million years ago and on today’s map.
Dots are fossil collections recorded in the Paleobiology Database. The “then” view moves today’s fossil sites back to their positions 75 million years ago (the time slice nearest the median age of the fossils) using the Merdith et al. (2021) plate model; positions are approximate. Open on the timeline map →
| Group | Theropods |
|---|---|
| Lived | 83.6–66 million years ago (Campanian to Maastrichtian) |
| Periods | Cretaceous |
| Family | Troodontidae |
| Named by | Leidy 1856 |
| Fossil records | 103 occurrences at 87 locations (PBDB) |
| Found in | Canada, United States, Russian Federation, China |
| Rock formations | Dinosaur Park, Oldman, Judith River, Hell Creek, Horseshoe Canyon, Two Medicine |
About Troodon
Troodon ( TROH-ə-don; Troödon in older sources) is a controversial genus of relatively small, bird-like theropod dinosaurs definitively known from the Campanian age of the Late Cretaceous period (about 77 million years ago). It includes at least one species, Troodon formosus, known from Montana. Discovered in October 1855, T. formosus was among the first dinosaurs found in North America, although it was thought to be a lizard until 1877.
Text in “About” is quoted from the Wikipedia article Troodon (revision 1379171153), licensed under CC BY-SA 4.0; introduction excerpted verbatim, formatting removed. Ages, family, authority and fossil records: Paleobiology Database, accessed 22 October 2026. Ages are those of the rock layers the fossils were found in.
