Nilwood is an incorporated town in Macoupin County, Illinois, United States. The population was 284 at the 2000 census.Nilwood is located at 39°23′50″N 89°48′28″W / 39.39722°N 89.80778°W / 39.39722; -89.80778.According to the 2010 census, Nilwood has a total area of 0.47 square miles, all land.As of the census of 2000, there were 284 people, 107 households, and 80 families residing in the town. The population density was 610.4 people per square mile. There were 117 housing units at an average density of 251.5/sq mi. The racial makeup of the town was 100.00% White. Hispanic or Latino of any race were 1.06% of the population.There were 107 households out of which 35.5% had children under the age of 18 living with them, 62.6% were married couples living together, 5.6% had a female householder with no husband present, and 25.2% were non-families. 19.6% of all households were made up of individuals and 9.3% had someone living alone who was 65 years of age or older.