A nearly continuous record of ¹⁰Be (half-life of 1.5 × 10⁶ years) concentrations is reported in the Greenland Ice Sheet Project 2 (GISP2) ice core for the time period between 3288 and 40,055 years B.P. The resolution is between 20 and 50 years in the Holocene. During the Pleistocene, sampling was coarser, with the resolution ranging between 50 and 200 years. Both concentrations and fluxes are reported. Concentrations of ¹⁰Be are observed to correlate strongly with δ¹⁸O and more weakly with snow accumulation rates. Beryllium 10 fluxes show less dependence than do concentrations on climate-related parameters. A good correlation exists between Δ¹⁴C and ¹⁰Be for centennial scale variations, which are most likely due to heliomagnetic modulation of the ¹⁰Be production rate in the atmosphere. There is no evidence of a long-term geomagnetic effect on the ¹⁰Be flux at GISP2. The interpretation of the record depends strongly on the model one uses to infer atmospheric ¹⁰Be concentrations from the measured concentrations in snow.