Willow Spring is an unincorporated community in southeastern Wake County, and western Johnston County North Carolina, United States. As of 2014, the population was 15,768 with population density of 379 base in NC Sperling's data. The Frank and Mary Smith House and Turner and Amelia Smith House, both listed on the National Register of Historic Places, are located in Willow Spring. Black Creek, part of the Neuse River, runs through Willow Spring. There are wetlands such as swamp and marsh surrounding the creek.