The land that today is known as Story County was originally prairie with the exception of some groves along the larger streams in the area. In 1846 the boundaries of Story County were established. The County has an area of 576 square miles and is square in shape.

The county was named after Joseph Story, a preeminent United States Supreme Court Justice, in 1853. The first settlers in Story County came mainly from Indiana, New York and Pennsylvania. Later, many Norwegians, Germans and Danes came directly from overseas and inhabited the area. The first large population influx occurred during the 1850's. Story County was not mentioned in the Federal Census in 1850, but figures from the State of Iowa put the population at 214 in 1852. By 1860 the population had increased to 4,501.

Three commissioners appointed by the Iowa legislature selected the location of county seat on June, 27 1853. The location was Nevada, Iowa. Nevada (pronounced Nah-Vay-Dah) was named after the Sierra Nevada mountain range in western California. What does the Sierra Nevada have to do with Iowa, you may ask? Many prominent locations from the Mexican-American War of the late 1840's inspired the naming of towns and counties in Iowa during this period.

Railroad construction did more to develop Story County, as it did for the entire American West, than anything else. The first railroad came to the county in 1864. Railroads were such a decisive factor in determining the location of towns that several communities in Story County moved to be closer to the rail line. Some flourishing little towns that were bypassed by the railroad soon disappeared. 

Although Nevada was long the population center of the county, Ames was the most widely known of the towns because of the busy railroad depot where travelers changed trains for all points north, south, east and west.

Story County consists of 16 townships and 15 incorporated cities, and 4 unincorporated towns. The population of 79,981 in the 2000 census consisted of 71,114 in urban areas and 8867 in rural areas.

As of the census2 of 2000, there were 79,981 people, 29,383 households, and 17,042 families residing in the county. The population density was 54/km (140/mi). There were 30,630 housing units at an average density of 21/km (54/mi). The racial makeup of the county was 91.14% White, 1.83% Black or African American, 0.16% Native American, 5.10% Asian, 0.03% Pacific Islander, 0.60% from other races, and 1.14% from two or more races. 1.55% of the population were Hispanic or Latino of any race.

There were 29,383 households out of which 27.30% had children under the age of 18 living with them, 49.60% were married couples living together, 5.90% had a female householder with no husband present, and 42.00% were non-families. 26.70% of all households were made up of individuals and 7.60% had someone living alone who was 65 years of age or older. The average household size was 2.39 and the average family size was 2.94.

In the county the population was spread out with 19.10% under the age of 18, 28.30% from 18 to 24, 25.50% from 25 to 44, 17.30% from 45 to 64, and 9.80% who were 65 years of age or older. The median age was 26 years. For every 100 females there were 104.60 males. For every 100 females age 18 and over, there were 104.40 males.

The median income for a household in the county was $40,442, and the median income for a family was $55,472. Males had a median income of $36,756 versus $26,941 for females. The per capita income for the county was $19,949. 14.10% of the population and 5.50% of families were below the poverty line. 6.80% of those under the age of 18 and 4.30% of those 65 and older were living below the poverty line