[2] In the Nebraska license plate system, Rock County is represented by the prefix 81 (it had the 81st-largest number of vehicles registered in the county when the license plate system was established in 1922).

The Niobrara River flows eastward along the northern boundary line of Rock County.

[5] Rock County is located in Nebraska's Outback region.

[6] As of the 2000 United States Census,[14] there were 1,756 people, 763 households, and 501 families in the county.

31.30% of all households were made up of individuals, and 15.90% had someone living alone who was 65 years of age or older.

In only one national election since 1916 has the county selected the Democratic Party candidate (as of 2024).