The name is properly pronounced "O-NEK-ah-ma", but some local business people have mirthfully utilized a common mispronunciation by tourists and have produced sweatshirts, t-shirts, and bumper stickers with the symbols "1," (pronounced 'ONE comma').
As of the census of 2000, there were 647 people, 239 households, and 152 families residing in the village. The population density was 1,083.9 per square mile (416.3/km²). There were 315 housing units at an average density of 527.7/sq mi (202.7/km²). The racial makeup of the village was 85.16% White, 0.15% African American, 0.46% Native American, 13.14% from other races, and 1.08% from two or more races. Hispanic or Latino of any race were 21.79% of the population.
There were 239 households out of which 22.2% had children under the age of 18 living with them, 49.0% were married couples living together, 12.1% had a female householder with no husband present, and 36.0% were non-families. 34.3% of all households were made up of individuals and 17.2% had someone living alone who was 65 years of age or older. The average household size was 2.11 and the average family size was 2.66.
In the village the population was spread out with 24.4% under the age of 18, 8.2% from 18 to 24, 24.9% from 25 to 44, 21.9% from 45 to 64, and 20.6% who were 65 years of age or older. The median age was 39 years. For every 100 females there were 115.0 males. For every 100 females age 18 and over, there were 103.8 males.
The median income for a household in the village was $29,091, and the median income for a family was $47,500. Males had a median income of $23,125 versus $15,455 for females. The per capita income for the village was $16,718. About 9.3% of families and 16.0% of the population were below the poverty line, including 24.5% of those under age 18 and 2.4% of those age 65 or over.