Racial and ethnic composition 2020 census As of the
2020 census, Diamond had a population of 2,640. The median age was 36.1 years. 27.8% of residents were under the age of 18 and 13.0% of residents were 65 years of age or older. For every 100 females, there were 103.5 males, and for every 100 females age 18 and over, there were 99.9 males. The population density was . There were 1,043 housing units at an average density of . 99.8% of residents lived in urban areas, while 0.2% lived in rural areas. There were 1,006 households in Diamond, of which 39.3% had children under the age of 18 living in them. Of all households, 48.9% were married-couple households, 19.2% were households with a male householder and no spouse or partner present, and 23.5% were households with a female householder and no spouse or partner present. About 26.3% of all households were made up of individuals, and 12.2% had someone living alone who was 65 years of age or older. There were 1,043 housing units, of which 3.5% were vacant. The homeowner vacancy rate was 1.1% and the rental vacancy rate was 7.7%.
Income and poverty The median income for a household in the village was $51,019, and the median income for a family was $73,750. Males had a median income of $53,148 versus $29,327 for females. The
per capita income for the village was $30,891. About 11.9% of families and 11.0% of the population were below the
poverty line, including 20.1% of those under age 18 and 9.2% of those age 65 or over. ==Education==