Monument is a city in Grant County, Oregon, United States. The population was 128 at the 2010 census. It is located near the confluence of the North and Middle Forks of the John Day River. Its post office was established in 1874 and named for a nearby mountain or rock formation.
According to the United States Census Bureau, the city has a total area of 0.51 square miles (1.32 km), all land. By road, Monument is 110 miles (180 km) southwest of Pendleton, about 64 miles (103 km) northwest of John Day, and about 156 miles (251 km) northeast of Bend.
As of the census of 2010, there were 128 people, 55 households, and 31 families residing in the city. The population density was 251.0 inhabitants per square mile (96.9/km). There were 82 housing units at an average density of 160.8 per square mile (62.1/km). The racial makeup of the city was 94.5% White, 0.8% Native American, 3.9% from other races, and 0.8% from two or more races. Hispanic or Latino of any race were 3.9% of the population.
There were 55 households of which 29.1% had children under the age of 18 living with them, 43.6% were married couples living together, 9.1% had a female householder with no husband present, 3.6% had a male householder with no wife present, and 43.6% were non-families. 38.2% of all households were made up of individuals and 12.7% had someone living alone who was 65 years of age or older. The average household size was 2.33 and the average family size was 3.23.
The median age in the city was 40.5 years. 24.2% of residents were under the age of 18; 5.6% were between the ages of 18 and 24; 26.6% were from 25 to 44; 27.4% were from 45 to 64; and 16.4% were 65 years of age or older. The gender makeup of the city was 54.7% male and 45.3% female.
As of the census of 2000, there were 151 people, 68 households, and 41 families residing in the city. The population density was 281.0 people per square mile (108.0/km²). There were 81 housing units at an average density of 150.7 per square mile (57.9/km²). The racial makeup of the city was 95.36% White, 3.97% Native American, and 0.66% from two or more races.
There were 68 households out of which 26.5% had children under the age of 18 living with them, 47.1% were married couples living together, 7.4% had a female householder with no husband present, and 39.7% were non-families. 32.4% of all households were made up of individuals and 11.8% had someone living alone who was 65 years of age or older. The average household size was 2.22 and the average family size was 2.78.
In the city, the population was spread out with 25.2% under the age of 18, 7.3% from 18 to 24, 27.2% from 25 to 44, 23.8% from 45 to 64, and 16.6% who were 65 years of age or older. The median age was 35 years. For every 100 females, there were 118.8 males. For every 100 females age 18 and over, there were 113.2 males.
The median income for a household in the city was $24,000, and the median income for a family was $45,714. Males had a median income of $38,750 versus $21,250 for females. The per capita income for the city was $15,814. There were 6.8% of families and 17.1% of the population living below the poverty line, including 19.2% of under eighteens and 8.0% of those over 64.