In 1917, the community was destroyed by a fire.
Sumpter is located on Oregon Route 410 (formerly Oregon Route 220).
There were 95 households out of which 6.3% had children under the age of 18 living with them, 49.5% were married couples living together, 2.1% had a female householder with no husband present, and 46.3% were non-families. 37.9% of all households were made up of individuals and 18.9% had someone living alone who was 65 years of age or older. The average household size was 1.80 and the average family size was 2.31.
In the city the population was spread out with 7.6% under the age of 18, 3.5% from 18 to 24, 17.0% from 25 to 44, 48.0% from 45 to 64, and 24.0% who were 65 years of age or older. The median age was 55 years. For every 100 females there were 125.0 males. For every 100 females age 18 and over, there were 122.5 males.
The median income for a household in the city was $27,188, and the median income for a family was $31,000. Males had a median income of $28,750 versus $35,625 for females. The per capita income for the city was $16,518. About 6.5% of families and 10.2% of the population were below the poverty line, including 36.4% of those under the age of eighteen and 7.0% of those sixty five or over.