This dataset includes groundwater level data from four wells located on a permafrost mound (lithalsa) and its surroundings, within the Tasiapik Valley, near the village of Umiujaq, Nunavik, Quebec, Canada. The water levels are measured continuously within an unconfined sandy aquifer at the top (1 well; Sommet 1/TOP 1) and the side (2 wells; Côté 1/SIDE 1, Côté 2/SIDE 2) of the permafrost mound. Additionally, the water level is measured in a well (Silt 1/SILT 1) installed in a confining silt layer located below the superficial aquifer. Data were collected from 16 July 2014 – 28 June 2021 with Solinst Levelogger® water level dataloggers. Soils stratigraphy and well construction details are given below. These data support the article Fortier et al. (2023).