Snow and first-year sea ice ridge thickness, draft and morphology were measured using a 2-inch ice drilling auger (Kovacs Enterprises) during walking surveys on first-year ice ridge during the MOSAiC expedition. Drilling was performed during January and February 2020 across three drilling transects located 20 m from each other. The investigated "Fort Ridge" was formed from late September to early October 2019 between second- and first-year ice. It was approximately 90–100 m long and 20–30 m wide. The ridge was located on drifting sea ice in the Arctic Ocean within the Central Observatory of MOSAiC. The table contains the event label (1), event ID (2), time (3), and global coordinates (4,5) of each drilling measurement. Each separate drilling hole has its number indicating cross-section and number within cross-section (6), and local coordinate X (7) in [m] and transect name (8). Global coordinates are given for the local coordinates of X = 22 m at the transect 1. For each drill hole, the depth relative to the waterline of the top (9) and bottom (10) interface of each separate layer is given together with its ice type (11). Ice types include snow, ice (with various resistance), and voids. Information about missing freeboard measurements is given in comments (12). In the case of no freeboard measurement, it was assumed as 10% of the maximum keel draft. The drill hole with local coordinates of X = 22 m at the transect 1 coincides with the ice mass balance buoy 2020T60 installation described in doi:10.1594/PANGAEA.924269.These measurements were performed as part of the project Ridges - Safe HAVens for ice-associated Flora and Fauna in a Seasonally ice-covered Arctic OCean (HAVOC), funded by the Research Council of Norway, project number: 280292).