The hillshade is a black-and-white image showing elevation changes in the landscape. It is created from a digital elevation model as if the elevation surface were illuminated by a hypothetical light source shining from the northwest.
Hillshades make it easier to visualize changes in elevation over a landscape. They can be used on their own or as a backdrop layer for other geographic data.
Hillshades were generated from a number of lidar datasets collected at different times. See the source metadata listed on the Minnesota lidar information webpage: https://www.mngeo.state.mn.us/chouse/elevation/lidar.html