2020 census As of the
2020 census, Monte Rio had a population of 1,080 and a population density of . 0.0% of residents lived in urban areas, while 100.0% lived in rural areas. The age distribution was 112 people (10.4%) under the age of 18, 45 people (4.2%) aged 18 to 24, 219 people (20.3%) aged 25 to 44, 409 people (37.9%) aged 45 to 64, and 295 people (27.3%) who were 65 years of age or older. The median age was 55.3 years. For every 100 females, there were 116.0 males, and for every 100 females age 18 and over there were 119.0 males age 18 and over.
2010 census The
2010 United States census reported that Monte Rio had a population of 1,152. The population density was . The racial makeup of Monte Rio was 1,047 (90.9%)
White, 10 (0.9%)
African American, 6 (0.5%)
Native American, 11 (1.0%)
Asian, 1 (0.1%)
Pacific Islander, 16 (1.4%) from
other races, and 61 (5.3%) from two or more races.
Hispanic or
Latino of any race were 79 persons (6.9%). The Census reported that 93.6% of the population lived in households and 6.4% lived in non-institutionalized group quarters. There were 576 households, out of which 85 (14.8%) had children under the age of 18 living in them, 151 (26.2%) were
opposite-sex married couples living together, 43 (7.5%) had a female householder with no husband present, 32 (5.6%) had a male householder with no wife present. There were 42 (7.3%)
unmarried opposite-sex partnerships, and 37 (6.4%)
same-sex married couples or partnerships. 247 households (42.9%) were made up of individuals, and 61 (10.6%) had someone living alone who was 65 years of age or older. The average household size was 1.87. There were 226
families (39.2% of all households); the average family size was 2.54. The population was spread out, with 132 people (11.5%) under the age of 18, 63 people (5.5%) aged 18 to 24, 253 people (22.0%) aged 25 to 44, 528 people (45.8%) aged 45 to 64, and 176 people (15.3%) who were 65 years of age or older. The median age was 50.7 years. For every 100 females, there were 119.8 males. For every 100 females age 18 and over, there were 125.2 males. There were 930 housing units at an average density of , of which 56.9% were owner-occupied and 43.1% were occupied by renters. The homeowner vacancy rate was 3.7%; the rental vacancy rate was 9.1%. 57.0% of the population lived in owner-occupied housing units and 36.5% lived in rental housing units.
2000 census As of the
census of 2000, the median income for a household in the CDP was $38,299, and the median income for a family was $46,336. Males had a median income of $29,135 versus $28,750 for females. The
per capita income for the CDP was $20,262. About 12.1% of families and 16.0% of the population were below the
poverty line, including 22.7% of those under age 18 and none of those age 65 or over. ==Government==