Lake Oswego is one of the most affluent suburbs of Portland. In 2000, the city had a median household income of $71,597, up from $57,499 in 1990. Additionally, as in the rest of the Portland metropolitan area, house prices have increased rapidly (as of June 2006); the median value in 2000 was $296,200, over twice what it was in 1990 ($142,600). The city has some of the highest-priced real estate in the state, particularly the homes overlooking the lake. The 2007 estimate was $750,000 for houses not on the lake and $1,000,250 for those on the lake. These are the most expensive averages for Oregon cities.
As of the census of 2000, there are 35,278 people in the city, organized into 14,769 households, and 9,665 families. The population density is 3,409.7 sq mi (8,831 km). There are 15,741 housing units at an average density of 1,521.4/sq mi (587.2/km²). The racial makeup of the city is 91.1% White, 4.6% Asian, 0.6% Black or African American, 0.3% Native American, 0.2% Pacific Islander, 0.7% from other races, and 2.5% from two or more races. 2.3% of the population are Hispanic or Latino of any race.
There are 14,769 households out of which 32.0% have children under the age of 18 living with them, 56.2% are married couples living together, 6.9% have a female householder with no husband present, and 34.6% are non-families. 27.9% of all households are made up of individuals and 7.9% have someone living alone who is 65 years of age or older. The average household size is 2.38 and the average family size is 2.95.
In the city the population is spread out with 24.8% under the age of 18, 6.1% from 18 to 24, 26.8% from 25 to 44, 31.0% from 45 to 64, and 11.4% who are 65 years of age or older. The median age is 41 years. For every 100 females there are 92.9 males. For every 100 females age 18 and over, there are 88.2 males.
The median income for a household in the city is $71,597, and the median income for a family is $94,587 (These figures had risen to $76,883 and $105,763 respectively as of a 2007 estimate). Males have a median income of $66,380 versus $41,038 for females. The per capita income for the city is $42,166. 3.4% of the population and 2.3% of families are below the poverty line. Out of the total population, 2.0% of those under the age of 18 and 4.0% of those 65 and older are living below the poverty line.