Greenhorn first appeared as a
census designated place in the
2000 U.S. census. The whole population lived in households. There were 108 households, out of which 18 (16.7%) had children under the age of 18 living in them, 47 (43.5%) were married-couple households, 7 (6.5%) were
cohabiting couple households, 16 (14.8%) had a female householder with no partner present, and 38 (35.2%) had a male householder with no partner present. 47 households (43.5%) were one person, and 13 (12.0%) were one person aged 65 or older. The average household size was 2.29. The age distribution was 54 people (21.9%) under the age of 18, 7 people (2.8%) aged 18 to 24, 62 people (25.1%) aged 25 to 44, 49 people (19.8%) aged 45 to 64, and 75 people (30.4%) who were 65years of age or older. The median age was 46.5years. For every 100 females, there were 120.5 males. The whole population lived in households, no one lived in non-institutionalized group quarters and no one was institutionalized. There were 106 households, 23 (21.7%) had children under the age of 18 living in them, 56 (52.8%) were
opposite-sex married couples living together, 4 (3.8%) had a female householder with no husband present, 4 (3.8%) had a male householder with no wife present. There were 7 (6.6%)
unmarried opposite-sex partnerships, and 1 (0.9%)
same-sex married couples or partnerships. 33 households (31.1%) were one person and 9 (8.5%) had someone living alone who was 65 or older. The average household size was 2.23. There were 64 families (60.4% of households); the average family size was 2.81. The age distribution was 43 people (18.2%) under the age of 18, 15 people (6.4%) aged 18 to 24, 47 people (19.9%) aged 25 to 44, 88 people (37.3%) aged 45 to 64, and 43 people (18.2%) who were 65 or older. The median age was 46.9 years. For every 100 females, there were 96.7 males. For every 100 females age 18 and over, there were 103.2 males. There were 140 housing units at an average density of 20.9 per square mile, of the occupied units 95 (89.6%) were owner-occupied and 11 (10.4%) were rented. The homeowner vacancy rate was 6.9%; the rental vacancy rate was 8.3%. 211 people (89.4% of the population) lived in owner-occupied housing units and 25 people (10.6%) lived in rental housing units. ==Politics==