As of the census of 2000, there were 238,314 people, 81,662 households, and 61,328 families residing in the county. The population density was 421 people per square mile (163/km²). There were 86,856 housing units at an average density of 154 per square mile (59/km²). The racial makeup of the county was 91.52% White, 1.05% Black or African American, 0.36% Native American, 2.09% Asian, 0.02% Pacific Islander, 3.48% from other races, and 1.48% from two or more races. 7.00% of the population were Hispanic or Latino of any race. 37.3% were of Dutch, 14.6% German, 6.2% English, 5.6% Irish and 5.4% American ancestry according to Census 2000. 91.5% spoke English and 5.4% Spanish as their first language.
There were 81,662 households out of which 39.30% had children under the age of 18 living with them, 64.60% were married couples living together, 7.50% had a female householder with no husband present, and 24.90% were non-families. 19.60% of all households were made up of individuals and 7.40% had someone living alone who was 65 years of age or older. The average household size was 2.81 and the average family size was 3.25.
Summer seasonal residents are also a member of the populous Ottawa County. Port Sheldon Township has many lakefront homes and other inland retreats that serve as summer getaways for residents of Grand Rapids, Detroit, and Chicago. No official statistics are compiled on seasonal residents.
In the county the population was spread out with 28.70% under the age of 18, 11.90% from 18 to 24, 29.30% from 25 to 44, 20.00% from 45 to 64, and 10.10% who were 65 years of age or older. The median age was 32 years. For every 100 females there were 97.00 males. For every 100 females age 18 and over, there were 94.20 males.
The median income for a household in the county was $52,347, and the median income for a family was $59,896. Males had a median income of $42,180 versus $27,706 for females. The per capita income for the county was $21,676. About 3.10% of families and 5.50% of the population were below the poverty line, including 4.70% of those under age 18 and 4.90% of those age 65 or over.