Monette is located in eastern Craighead County at . According to the United States Census Bureau, the city has a total area of, of which, or 0.19%, is water. Ecologically, Monette is located within the St. Francis Lowlands ecoregion within the larger Mississippi Alluvial Plain. The St. Francis Lowlands are a flat region mostly covered with row crop agriculture today, though also containing sand blows and sunken lands remaining from the 1811–12 New Madrid earthquakes. Waterways have mostly been channelized, causing loss of aquatic and riparian wildlife habitat. The St. Francis Sunken Lands Wildlife Management Area, which preserves some of the bottomland hardwood forest typical of this ecoregion prior to development for row agriculture lies just west of Monette along the St. Francis River.
As of the census of 2009, there were 1,247 people,529 households, and 321 families residing in the city. The population density was 721.8 people per square mile. There were 572 housing units at an average density of 348.3/sq mi. The racial makeup of the city was 96.61% White, 0.08% Black or African American, 0.08% Native American, 1.44% from other races, and 1.78% from two or more races. 2.63% of the population were Hispanic or Latino of any race. There were 525 households out of which 23.8% had children under the age of 18 living with them, 47.2% were married couples living together, 10.7% had a female householder with no husband present, and 39.6% were non-families. 37.9% of all households were made up of individuals and 24.4% had someone living alone who was 65 years of age or older. The average household size was 2.12 and the average family size was 2.78. In the city, the population was spread out with 19.7% under the age of 18, 7.3% from 18 to 24, 23.6% from 25 to 44, 23.7% from 45 to 64, and 25.8% who were 65 years of age or older. The median age was 44 years. For every 100 females, there were 76.5 males. For every 100 females age 18 and over, there were 73.4 males. The median income for a household in the city was $27,500, and the median income for a family was $33,796. Males had a median income of $28,375 versus $20,109 for females. The per capita income for the city was $16,517. About 13.3% of families and 16.4% of the population were below the poverty line, including 20.8% of those under age 18 and 25.7% of those age 65 or over.
