Gensburg Markham Prairie comprises over 100 acres of well-preserved tallgrass prairie and wetland south of Chicago and is one of the Indian Boundary Prairies in Illinois. A U.S. National Natural Landmark, this site is valuable as a sentinel ecosystem for changing regional climate and a reference ecosystem for restoration and management of urban prairie nature preserves. In June of 2016, 10 piezometers containing water level sensors (InSitu LevelTroll 400 pressure transducers) were installed throughout the prairie, in addition to 8 of the same sensors deployed in ditches and surface channels in and around the prairie. The installation coincided with soil sampling and manual-visual characterization at each well location. Each sensor collects a water level measurement every 30 minutes. This installation and sampling campaign is a part of larger effort to assess surface water and groundwater dynamics in urban environments. Additional sensors, including soil moisture and electrical conductivity probes and a rain gauge, provide supplementary data for this project. This resource includes one year of data, from the installation of the sensors to the same date the following summer, capturing the effects of an unusually warm winter in the Chicago metro with very little snow and no extreme temperatures.