The Hyde Park mastodon was discovered in 1999 when several bones were recovered from spoil produced during deepening of a recreational pond in eastern New York. Controlled excavation in 2000 located the minimally disturbed, primary bone concentration and allowed in situ documentation prior to removal. The specimen is an essentially complete, mature male Mammut americanum, radiocarbon dated at about 11,480 yr BP. The state of eruption and wear of its molar dentition is compatible with Laws’ relative age category XXII for African elephants (roughly 39 years old, although studies of annual increments in tusks suggest this stage of tooth wear was achieved up to ten years earlier in mastodons). Missing bones are limited to some of the small tail vertebrae and some foot bones. The specimen’s completeness makes it an important reference for documentation of morphologic gradients in ribs, vertebrae, and digital elements. Spatial relationships of bones at the site presented a complex combination of primary articulation and disarticulation with limited displacement – an arrangement compatible with progressive detachment of elements from a floating carcass restricted to one location by grounding of the tusks as buoyancy was lost from the carcass. Some bones display backhoe damage, but most are free of postmortem modification. In this respect, they contrast markedly with the condition of bones comprising partial mastodon skeletons interpreted as having been butchered by Paleoindians. Several instances of probable perimortem bone damage may represent injuries suffered during combat between musth males. The specimen’s main significance may be as a “control sample” representing normal mortality without intervention by humans.