jats:p jats:italicArthropleura</jats:italic> is a genus of giant myriapods that ranged from the early Carboniferous to Early Permian, with some individuals attaining lengths >2 m. Although most of the known fossils of the genus are disarticulated and occur primarily in late Carboniferous (Pennsylvanian) strata, we report here partially articulated jats:italicArthropleura</jats:italic> remains from the early Carboniferous Stainmore Formation (Serpukhovian; Pendleian) in the Northumberland Basin of northern England. This 76 × 36 cm specimen represents part of an exuvium and is notable because only two comparably articulated giant jats:italicArthropleura</jats:italic> fossils are previously known. It represents one of the largest known arthropod fossils and the largest arthropleurid recovered to date, the earliest (Mississippian) body fossil evidence for gigantism in jats:italicArthropleura</jats:italic> , and the first instance of a giant arthropleurid body fossil within the same regional sedimentary succession as the large arthropod trackway jats:italicDiplichnites cuithensis</jats:italic> . The remains represent 12–14 anterior jats:italicArthropleura</jats:italic> tergites in the form of a partially sand-filled dorsal exoskeleton. The original organism is estimated to have been 55 cm in width and up to 2.63 m in length, weighing jats:italicc.</jats:italic> 50 kg. The specimen is preserved partially in three dimensions within fine sandstone and has been moderately deformed by synsedimentary tectonics. Despite imperfect preservation, the specimen corroborates the hypothesis that jats:italicArthropleura</jats:italic> had a tough, sclerotized exoskeleton. Sedimentological evidence for a lower delta plain depositional environment supports the contention that jats:italicArthropleura</jats:italic> preferentially occupied open woody habitats, rather than swampy environments, and that it shared such habitats with tetrapods. When viewed in the context of all the other global evidence for jats:italicArthropleura,</jats:italic> the specimen contributes to a dataset that shows the genus had an equatorially restricted palaeogeographical range, achieved gigantism prior to late Paleozoic peaks in atmospheric oxygen, and was relatively unaffected by climatic events in the late Carboniferous, prior to its extinction in the early Permian. </jats:p> <jats:p content-type="supplementary-material"> jats:boldSupplementary material:</jats:bold> Images of 3D mesh model of jats:italicArthropleura</jats:italic> are available at <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="https://doi.org/10.6084/m9.figshare.c.5715450">https://doi.org/10.6084/m9.figshare.c.5715450</jats:ext-link> </jats:p>