View source for Grannis, Arkansas

===2000 census===
{{US Census population
| align = left
| 1940 = 225
| 1950 = 193
| 1960 = 185
| 1970 = 177
| 1980 = 349
| 1990 = 507
| 2000 = 575
| 2010 = 554
| 2020 = 496
| estyear = 2025
| estimate = 498
| estref = {{increase}}
| footnote = U.S. Decennial Census<ref name="DecennialCensus">{{cite web|url=https://www.census.gov/programs-surveys/decennial-census.html|title=Census of Population and Housing|publisher=Census.gov|access-date=June 4, 2015}}</ref>
}}
As of the [[census]]<ref name="GR2">{{cite web|url=https://www.census.gov |publisher=[[United States Census Bureau]] |access-date=January 31, 2008 |title=U.S. Census website }}</ref> of 2000, there were 575 people, 210 households, and 164 families residing in the city.  The population density was {{convert|66.6|PD/sqmi|PD/km2|sp=us|adj=off}}.  There were 254 housing units at an average density of {{convert|29.4|/sqmi|/km2|sp=us|adj=off}}.  The racial makeup of the city was 78.78% [[Race (United States Census)|White]], 0.52% [[Race (United States Census)|Black]] or [[Race (United States Census)|African American]], 4.35% [[Race (United States Census)|Native American]], 0.17% [[Race (United States Census)|Pacific Islander]], 14.09% from [[Race (United States Census)|other races]], and 2.09% from two or more races.  16.52% of the population were [[Race (United States Census)|Hispanic]] or [[Race (United States Census)|Latino]] of any race.

There were 210 households, out of which 37.6% had children under the age of 18 living with them, 68.1% were [[Marriage|married couples]] living together, 7.6% had a female householder with no husband present, and 21.9% were non-families. 18.1% of all households were made up of individuals, and 4.8% had someone living alone who was 65 years of age or older.  The average household size was 2.74 and the average family size was 3.10.

In the city, the population was spread out, with 26.6% under the age of 18, 11.5% from 18 to 24, 26.1% from 25 to 44, 24.2% from 45 to 64, and 11.7% who were 65 years of age or older.  The median age was 32 years. For every 100 females, there were 101.0 males.  For every 100 females age 18 and over, there were 103.9 males.

The median income for a household in the city was $29,083, and the median income for a family was $30,893. Males had a median income of $22,500 versus $17,000 for females. The [[per capita income]] for the city was $14,642.  About 15.1% of families and 15.8% of the population were below the [[poverty line]], including 22.7% of those under age 18 and 19.4% of those age 65 or over.