As of the 2020 census, the city of Plainview, NE, had 1,282 people, 633 households and 602 housing units in city limits. The racial makeup of the Plainview was 95 percent White, 0.8 percent African American, 0.3 percent Native American, 0.3 percent Asian, .2 percent from other races and 3.4 percent from two or more races.

In the 633 households there were 398 families. 27.6 percent had children under the age of 18 living with them, 43.4 percent were married couples living together, 25.8 percent had a female householder with no husband present and 21.2 percent had a male householder with no wife present. The average family size of 2.73.

The median age in Plainview was 39 years. There were 36.6 percent of residents under the age of 18, 72.4 percent between the ages of 18 and 64, and 22.7 percent 65 years of age or older. 

The median household income of Plainview residents was $46,542. About 17.2 percent of Plainview residents live in poverty.

As of the 2010 census, the city of Plainview, NE, had 1,246 people, 562 households and 334 families residing in the city limits. The population density was 1,153.7 inhabitants per square mile with 656 housing units. The racial makeup of the Plainview was 98.2 percent White, 0.3 percent African American, 0.2 percent Native American, 0.2 percent Asian, 0.6 percent from other races and 0.6 percent from two or more races.

In the 562 households, 24.0 percent had children under the age of 18 living with them, 49.5 percent were married couples living together, 6.9 percent had a female householder with no husband present, 3.0 percent had a male householder with no wife present, and 40.6 percent were non-families. The average household size was 2.16 with an average family size of 2.79.

The median age in Plainview was 46.7 years. There were 21.7 percent of residents under the age of 18, 5.4 percent between the ages of 18 and 24, 21.2 percent from 25 to 44, 26.4 percent  from 45 to 64, and 25.4 percent 65 years of age or older. Plainview was 48.4 percent males and 51.6 percent female.

The median household income of Plainview residents was $35,875. About 15.1 percent of Plainview residents live in poverty.

In 2000, Plainview had 1,353 people, 588 households and 362 families. The population density was 1,249.1 people per square mile with 656 housing units. The racial makeup of Plainview was 97.71 percent White, 0.15 percent African American, 1.03 percent Native American, 0.44 percent Asian, and 0.67 percent from two or more races.

In the 588 households, 27.0 percent had children under the age of 18 living with them, 53.4 percent were married couples living together, 6.3 percent had a female householder with no husband present and 38.3 percent were non-families. The average household size was 2.22 with average family size was 2.92.

The median age in Plainview was 43 years. For every 100 females, there were 86.4 males. And for every 100 females age 18 and over, there were 78.0 males.

The median income for a household in the city was $27,056, and the median income for a family was $35,625. The per capita income for the city was $15,814. About 8.0% of families and 13.4% of the population were below the poverty line.