Abstract: The KN223 research cruise on board the R/V Knorr (Chief scientist Richard W. Murray; Principal investigators: Arthur J. Spivack, Steven D’Hondt, Robert A. Pockalny took place in October-December 2014 and had as primary goal to collect sedimentary pore water from a series of sites in the North Atlantic and determine if these samples can be used to (1) document how deep Atlantic meridional overturning circulation (AOM) of the last glacial maximum differed from that of the present, and (2) directly test the influence of last glacial maximum AMOC on atmospheric CO2 (via the pre-formed NO3- content of deep and intermediate water in the LGM North Atlantic). Geochemical measurements were performed at 9 sites across the North Atlantic, on 6 Multicores, 8 Gravity cores, and 9 Long Cores. Here we present shipboard porewater density, sulfate anomaly and concentration, alkalinity, dissolved inorganic carbon, and formation factor data. Porewater concentrations of sodium, magnesium, calcium, and potassium measured post-expedition are also included. Other Description: D’Hondt, S., R. Pockalny, V.M. Fulfer, A.J. Spivack, 2019, Subseafloor life and its biogeochemical impacts, Nat. Comm., 10, 3519, 10.1038/s41467-019-11450-z.; Buchwald, C., K. Homola, A. J. Spivack, E. R. Estes, R. W. Murray, S. D. Wankel, 2018, Isotopic constraints on nitrogen transformation rates in the deep sedimentary marine biosphere, G. Biogeo. Cyc., 10.1029/2018GB005948.; D’Hondt, S., F. Inagaki, C.A. Zarikian, L.J. Abrams, N. Dubois, T. Engelhardt, H. Evans, T. Ferdelman, B. Gribsholt, R.N. Harris, B.W. Hoppie, J.H. Hyun, J. Kallmeyer, J. Kim, J.E. Lynch, C.C. McKinley, S. Mitsunobu, Y. Morono, R.W. Murray, R. Pockalny, J. Sauvage, T. Shimono, F. Shiraishi, D.C. Smith, C.E. Smith-Duque, A.J. Spivack, B.O. Steinsbu, Y. Suzuki, M. Szpak, L. Toffin, G. Uramoto, Y.T. Yamaguchi, G.L. Zhang, X.H. Zhang & W. Ziebis, 2015, Presence of oxygen and aerobic communities from sea floor to basement in deep-sea sediments, Nature Geoscience, 8, 299–304, 10.1038/ngeo2387.