Merrick County is part of the Grand Island, Nebraska Micropolitan Statistical Area.
In the Nebraska license plate system, Merrick County is represented by the prefix 46 (it had the forty-sixth-largest number of vehicles registered in the county when the license plate system was established in 1922).
1860 - 109 1870 - 557 1880 - 5,341 1890 - 8,758 1900 - 9,255 1910 - 10,379 1920 - 10,763 1930 - 10,619 1940 - 9,354 1950 - 8,812 1960 - 8,363 1970 - 8,751 1980 - 8,945 1990 - 8,049 2000 - 8,204
As of the census of 2000, there were 8,204 people, 3,209 households, and 2,307 families residing in the county. The population density was 17 people per square mile (7/km²). There were 3,649 housing units at an average density of 8 per square mile (3/km²). The racial makeup of the county was 98.32% White, 0.22% Black or African American, 0.10% Native American, 0.21% Asian, 0.01% Pacific Islander, 0.67% from other races, and 0.48% from two or more races. 2.05% of the population were Hispanic or Latino of any race.
There were 3,209 households out of which 33.30% had children under the age of 18 living with them, 61.10% were married couples living together, 6.50% had a female householder with no husband present, and 28.10% were non-families. 25.00% of all households were made up of individuals and 13.10% had someone living alone who was 65 years of age or older. The average household size was 2.51 and the average family size was 2.99.
In the county the population was spread out with 27.50% under the age of 18, 6.40% from 18 to 24, 24.70% from 25 to 44, 23.80% from 45 to 64, and 17.50% who were 65 years of age or older. The median age was 39 years. For every 100 females there were 95.90 males. For every 100 females age 18 and over, there were 94.90 males.
The median income for a household in the county was $34,961, and the median income for a family was $39,729. Males had a median income of $26,998 versus $19,828 for females. The per capita income for the county was $15,958. About 7.00% of families and 8.90% of the population were below the poverty line, including 9.70% of those under age 18 and 9.20% of those age 65 or over.