The city was named for U.S. Senator Fred Dubois.
Six miles (10 km) north of town is the U.S. Sheep Experiment Station, the county's second largest employer. The station studies sheep breeds to support U.S. sheep farmers. Dubois is near the Caribou-Targhee National Forest, which calls one of its administrative units the Dubois ranger district.
According to the United States Census Bureau, the city has a total area of 2.2 square miles (5.8 km²), all of it land.
There were 214 households out of which 49.1% had children under the age of 18 living with them, 60.7% were married couples living together, 10.3% had a female householder with no husband present, and 22.9% were non-families. 19.6% of all households were made up of individuals and 11.2% had someone living alone who was 65 years of age or older. The average household size was 3.02 and the average family size was 3.52.
In the city the population was spread out with 36.0% under the age of 18, 8.0% from 18 to 24, 27.2% from 25 to 44, 18.4% from 45 to 64, and 10.4% who were 65 years of age or older. The median age was 30 years. For every 100 females there were 107.4 males. For every 100 females age 18 and over, there were 98.1 males.
The median income for a household in the city was $29,167, and the median income for a family was $30,417. Males had a median income of $24,444 versus $21,000 for females. The per capita income for the city was $10,389. About 21.4% of families and 20.9% of the population were below the poverty line, including 25.7% of those under age 18 and 14.1% of those age 65 or over.