Surface level measurements of the Halema'uma'u lava lake, Hawaii. Surface level was measured from a site at the crater rim (19.40452 N 155.27944 W 1125 M a.s.l) using the Eredar radar system, a ground-based X-band FMCW radar (described in detail here: https://doi.org/10.1029/2018GL079177). Due to technical problems, the radar did not acquire continuously throughout its deployment. The dataset contains three blocks of successful continuous measurement periods (all times in UTC): 10 Jan 22:18 -> 11 Jan 08:46 11 Jan 21:24 -> 12 Jan 22:49 14 Jan 20:27 -> 14 Jan 23:01 Measurements were taken at a rate of ~1 Hz, using a 20 ms 400 MHz bandwidth Linear Frequency Modulated chirp centred at 10.25 GHz.