The T-3 (Fletcher's) Ice Island in the Arctic Ocean was the site of a scientific research station re-established by the Naval Arctic Research Laboratory starting in 1962. Starting in 1963, the USGS acquired marine heat flow data and coincident sediment cores at sites in Canada Basin, Nautilus Basin, Mendeleev Ridge, and Alpha Ridge as the ice island drifted in the Amerasian Basin. At least 584 heat flow penetrations were attempted, and data were reported at 356 of these. This dataset is the enhanced version of the original data table from Lachenbruch and others (2019; see cross-reference), incorporating additional information such as the probable dates of measurement, physiographic province and surficial geology at each station, and the length of recovered cores. In addition, this dataset converts the original units to SI units and the positions to decimal degrees.