Riggins is midway in the 300 mile (483 km) drive from Boise to Moscow, home of the University of Idaho, making it a popular refueling stop for students from the Treasure Valley.
As of the census of 2000, there were 410 people, 204 households, and 111 families residing in the city. The population density was 1,361.3 people per square mile (527.7/km²). There were 253 housing units at an average density of 840.0/sq mi (325.6/km²). The racial makeup of the city was 98.29% White, 0.49% Native American, 0.24% from other races, and 0.98% from two or more races.
There were 204 households out of which 15.7% had children under the age of 18 living with them, 45.1% were married couples living together, 6.9% had a female householder with no husband present, and 45.1% were non-families. 39.2% of all households were made up of individuals and 23.5% had someone living alone who was 65 years of age or older. The average household size was 2.01 and the average family size was 2.64.
In the city the population was spread out with 17.6% under the age of 18, 3.2% from 18 to 24, 18.5% from 25 to 44, 33.2% from 45 to 64, and 27.6% who were 65 years of age or older. The median age was 52 years. For every 100 females there were 100.0 males. For every 100 females age 18 and over, there were 101.2 males.
The median income for a household in the city was $20,972, and the median income for a family was $30,000. Males had a median income of $27,361 versus $16,250 for females. The per capita income for the city was $17,330. About 19.2% of families and 25.3% of the population were below the poverty line, including 50.0% of those under age 18 and 9.5% of those age 65 or over.