According to the 2010 census, Willow Springs has a total area of 4.116 square miles (10.66 km2), of which 4.01 square miles (10.39 km2) (or 97.42%) is land and 0.106 square miles (0.27 km2) (or 2.58%) is water.
The top five ancestries reported in Willow Springs as of the 2000 census were Polish (25.3%), German (19.6%), Irish (12.6%), Italian (11.3%) and Czech (6.9%).
There were 1,948 households out of which 29.5% had children under the age of 18 living with them, 59.6% were married couples living together, 7.4% had a female householder with no husband present, and 29.1% were non-families. 24.8% of all households were made up of individuals and 6.6% had someone living alone who was 65 years of age or older. The average household size was 2.58 and the average family size was 3.12.
In the village the population was spread out with 22.5% under the age of 18, 6.9% from 18 to 24, 29.0% from 25 to 44, 30.8% from 45 to 64, and 10.8% who were 65 years of age or older. The median age was 41 years. For every 100 females there were 101.2 males. For every 100 females age 18 and over, there were 99.7 males.
The median income for a household in the village was $58,322, and the median income for a family was $66,886. Males had a median income of $48,776 versus $35,466 for females. The per capita income for the village was $30,394. About 5.9% of families and 6.2% of the population were below the poverty line, including 8.1% of those under age 18 and 6.7% of those age 65 or over.
A majority of public elementary and middle school students attend Willow Springs School in District 108 or Pleasantdale Elementary in District 107. At the high school level, District 108 students move onto Argo Community High School (District 217) in Summit, IL, and District 107 students move onto Lyons Township High School (District 204) in La Grange/Western Springs, IL. Another portion of students attend Amos Alonzo Stagg High School (District 230) in Palos Hills, IL.