A major railroad terminated in Casa Grande, which was originally named "Terminus".

One of the founding fathers of Casa Grande was Thompson Rodney Peart. Peart Road, Peart Park, and the Peart Center, all of which are notable fixtures of Casa Grande, are named after him.

Casa Grande was home to a collective farm society which was part of the New Deal.

Casa Grande is home to Francisco Grande Hotel & Golf Resort, former spring training location for the San Francisco Giants. Then owner, Horace Stoneham, began developing the property in 1959. The first exhibition game was played in Casa Grande in 1961, with Willie Mays hitting a 375-foot (114 m) home run. The San Francisco Giants no longer play at Francisco Grande, but the pool remains in a baseball bat and ball shape in memory of the past ballgames.

Casa Grande is located at 32°53′09″N 111°44′38″W / 32.885952°N 111.743851°W / 32.885952; -111.743851.

According to the United States Census Bureau, the city has a total area of 48.2 square miles (124.8 km²), all of it land.

Casa Grande is in an arid desert climate. In January, the normal high temperature is 65 with a normal low of 38. In July, the normal high temperature is 105 with a normal low of 78. Annual rainfall is around 10 inches (250 mm).

As of the census of 2000, there were 25,224 people, 8,920 households, and 6,547 families residing in the city. The population density was 523.7 people per square mile (202.2/km²). There were 11,041 housing units at an average density of 229.2/sq mi (88.5/km²). The racial makeup of the city was 64.90% White, 4.27% Black or African American, 4.91% Native American, 1.17% Asian, 0.10% Pacific Islander, 21.09% from other races, and 3.56% from two or more races. 39.13% of the population were Hispanic or Latino of any race.

There were 8,920 households out of which 37.1% had children under the age of 18 living with them, 52.3% were married couples living together, 15.1% had a female householder with no husband present, and 26.6% were non-families. 21.7% of all households were made up of individuals and 8.9% had someone living alone who was 65 years of age or older. The average household size was 2.80 and the average family size was 3.24.

In the city the population was spread out with 30.9% under the age of 18, 9.3% from 18 to 24, 26.4% from 25 to 44, 19.6% from 45 to 64, and 13.8% who were 65 years of age or older. The median age was 32 years. For every 100 females there were 97.1 males. For every 100 females age 18 and over, there were 91.5 males.