(Platte is derived from the French word for a low, shallow, or intermittent stream.)

[4] The county's southwestern border with Kansas is formed by the Missouri River.

As of the census[10] of 2000, there were 73,781 people, 29,278 households, and 20,231 families residing in the county.

The racial makeup of the county was 91.45% White, 3.49% Black or African American, 0.46% Native American, 1.48% Asian, 0.20% Pacific Islander, 1.05% from other races, and 1.87% from two or more races.

24.90% of all households were made up of individuals, and 6.00% had someone living alone who was 65 years of age or older.

School districts (all full K-12) include:[12] The Republican Party controls politics at the local level in Platte County.

Senator Hillary Clinton (D-New York) received more votes, a total of 5,434, than any candidate from either party in Platte County during the 2008 presidential primary.