Lake County is part of the Cleveland–Elyria–Mentor Metropolitan Statistical Area.
As of the census of 2000, there were 227,511 people, 89,700 households, and 62,520 families residing in the county. The population density was 997 people per square mile (385/km²). There were 93,487 housing units at an average density of 410 per square mile (158/km²). The racial makeup of the county was 95.40% White, 1.99% Black or African American, 0.11% Native American, 0.90% Asian, 0.02% Pacific Islander, 0.66% from other races, and 0.92% from two or more races. 1.70% of the population were Hispanic or Latino of any race. 18.5% were of German, 14.6% Italian, 12.7% Irish, 8.1% English, 6.2% Polish, 5.7% American and 5.4% Slovene ancestry according to Census 2000. 93.6% spoke English and 1.9% Spanish as their first language.
There were 89,700 households out of which 31.10% had children under the age of 18 living with them, 56.10% were married couples living together, 10.00% had a female householder with no husband present, and 30.30% were non-families. 25.60% of all households were made up of individuals and 9.80% had someone living alone who was 65 years of age or older. The average household size was 2.50 and the average family size was 3.03.
In the county, the population was spread out with 24.20% under the age of 18, 7.30% from 18 to 24, 29.70% from 25 to 44, 24.70% from 45 to 64, and 14.10% who were 65 years of age or older. The median age was 39 years. For every 100 females there were 94.50 males. For every 100 females age 18 and over, there were 91.50 males.
The median income for a household in the county was $48,763, and the median income for a family was $57,134. Males had a median income of $40,916 versus $28,434 for females. The per capita income for the county was $23,160. About 3.50% of families and 5.10% of the population were below the poverty line, including 6.50% of those under age 18 and 5.40% of those age 65 or over.
Laketran is the transit agency servicing Lake County. Interstate 90 runs northeast/southwest through Lake County, roughly parallel to State Route 2; together these roads make up the major traffic arteries in the county. There is currently no passenger rail service in Lake County.