As of the census² of 2000, there were 238,994 people, 71,201 households, and 59,239 families residing in the county. The population density was 785 people per square mile (303/km²). There were 74,114 housing units at an average density of 243 per square mile (94/km²). The racial makeup of the county was 92.26% White, 1.09% Black or African American, 0.58% Native American, 1.53% Asian, 0.27% Pacific Islander, 2.30% from other races, and 1.97% from two or more races. 5.42% of the population were Hispanic or Latino of any race. In 2005 88.6% of Davis County's population was non-Hispanic whites. 1.2% of the population was African-American. 1.8% of the population was Asian. 6.6% of the population was Latino.

There were 71,201 households out of which 49.50% had children under the age of 18 living with them, 70.80% were married couples living together, 9.20% had a female householder with no husband present, and 16.80% were non-families. There are 1,636 unmarried partner households in Davis County: 1,410 heterosexual, 132 same-sex male, and 94 same-sex female. 13.60% of all households were made up of individuals and 4.60% had someone living alone who was 65 years of age or older. The average household size was 3.31 and the average family size was 3.67.

In the county, the population was spread out with 35.10% under the age of 18, 12.20% from 18 to 24, 28.20% from 25 to 44, 17.10% from 45 to 64, and 7.30% who were 65 years of age or older. The median age was 27 years. For every 100 females there were 100.90 males. For every 100 females age 18 and over, there were 98.50 males.

The median income for a household in the county was $53,726, and the median income for a family was $58,329. Males had a median income of $40,913 versus $25,904 for females. The per capita income for the county was $19,506. 5.10% of the population and 4.00% of families were below the US Federal poverty line. 5.90% of those under the age of 18 and 4.10% of those 65 and older were living below the poverty line.

By 2006 276,259 people lived in Davis County, representing a growth of 15.6% since the last census, slightly more than the growth rate for Utah overall.

Source - http://en.wikipedia.org/wiki/Davis_County%2C_Utah