New Underwood (Lakota: wóȟešma tȟéča; "new undergrowth") is a city in Pennington County, South Dakota, United States. The population was 660 at the 2010 census.
New Underwood got its start circa 1906. The city was named for John Underwood, a cattleman.
New Underwood is located at 44°5′38″N 102°50′3″W (44.093843, -102.834055).
According to the United States Census Bureau, the city has a total area of 1.00 square mile (2.59 km2), all land.
New Underwood has been assigned the ZIP code 57761 and the FIPS place code 45060.
As of the census of 2010, there were 660 people, 248 households, and 162 families living in the city. The population density was 660.0 inhabitants per square mile (254.8/km2). There were 280 housing units at an average density of 280.0 per square mile (108.1/km2). The racial makeup of the city was 89.5% White, 6.4% Native American, 0.2% Asian, 0.8% from other races, and 3.2% from two or more races. Hispanic or Latino of any race were 2.7% of the population.
There were 248 households, of which 34.3% had children under the age of 18 living with them, 47.6% were married couples living together, 13.7% had a female householder with no husband present, 4.0% had a male householder with no wife present, and 34.7% were non-families.