Two important Republican politicians came from Platte County: former Governor Jim Geringer, who served from 1995-2003) and former State Representatives Harold Hellbaum, who served from 1963-1977 and was Speaker of the House at the end of his tenure.
Platte County was also the birthplace of Larry Birleffi (1918-2008), the "Voice of the University of Wyoming Cowboys" from 1947-1986.
As of the census of 2000, there were 8,807 people, 3,625 households, and 2,494 families residing in the county. The population density was 4 people per square mile (2/km²). There were 4,528 housing units at an average density of 2 per square mile (1/km²). The racial makeup of the county was 96.18% White, 0.16% Black or African American, 0.50% Native American, 0.17% Asian, 0.02% Pacific Islander, 1.69% from other races, and 1.27% from two or more races. 5.28% of the population were Hispanic or Latino of any race. 31.7% were of German, 13.4% Irish, 11.3% English and 7.5% American ancestry according to Census 2000.
There were 3,625 households out of which 30.00% had children under the age of 18 living with them, 58.90% were married couples living together, 6.80% had a female householder with no husband present, and 31.20% were non-families. 27.30% of all households were made up of individuals and 13.20% had someone living alone who was 65 years of age or older. The average household size was 2.40 and the average family size was 2.92.
In the county the population was spread out with 25.40% under the age of 18, 6.60% from 18 to 24, 24.30% from 25 to 44, 27.30% from 45 to 64, and 16.60% who were 65 years of age or older. The median age was 41 years. For every 100 females there were 97.40 males. For every 100 females age 18 and over, there were 96.50 males.
The median income for a household in the county was $33,866, and the median income for a family was $41,449. Males had a median income of $31,484 versus $19,635 for females. The per capita income for the county was $17,530. About 8.50% of families and 11.70% of the population were below the poverty line, including 15.90% of those under age 18 and 12.20% of those age 65 or over.