Demographics

See also: List of Massachusetts locations by per capita income Historical population Year Pop.   ±%   1790 2,115 —     1800 2,453 +16.0% 1810 2,323 −5.3% 1820 3,295 +41.8% 1830 6,072 +84.3% 1840 8,409 +38.5% 1850 15,215 +80.9% 1860 26,060 +71.3% 1870 39,634 +52.1% 1880 52,669 +32.9% 1890 70,028 +33.0% 1900 91,886 +31.2% 1910 104,839 +14.1% 1920 109,694 +4.6% 1930 113,643 +3.6% 1940 110,879 −2.4% 1950 120,740 +8.9% 1960 107,716 −10.8% 1970 100,361 −6.8% 1980 95,322 −5.0% 1990 95,802 +0.5% 2000 101,355 +5.8% 2010 105,162 +3.8% Source: United States Census records and Population Estimates Program data.

As of the census of 2010, there were 105,162 people, 44,032 households, and 17,420 families residing in the city. The population density was 16,422.08 people per square mile (6,341.98/km²), making Cambridge the fifth most densely populated city in the US and the second most densely populated city in Massachusetts behind neighboring Somerville. There were 47,291 housing units at an average density of 7,354.7 per square mile (2,840.3/km²). The racial makeup of the city was 66.60% White, 11.70% Black or African American, 0.20% Native American, 15.10% Asian, 0.01% Pacific Islander, 2.10% from other races, and 4.30% from two or more races. 7.60% of the population were Hispanic or Latino of any race. Non-Hispanic Whites were 62.1% of the population in 2010, down from 89.7% in 1970. This rather closely parallels the average racial demographics of the United States as a whole, although Cambridge has significantly more Asians than the average, and fewer Hispanics and Caucasians. 11.0% were of Irish, 7.2% English, 6.9% Italian, 5.5% West Indian and 5.3% German ancestry according to Census 2000. 69.4% spoke English, 6.9% Spanish, 3.2% Chinese or Mandarin, 3.0% Portuguese, 2.9% French Creole, 2.3% French, 1.5% Korean, and 1.0% Italian as their first language.

There were 44,032 households out of which 16.9% had children under the age of 18 living with them, 28.9% were married couples living together, 8.4% had a female householder with no husband present, and 60.4% were non-families. 40.7% of all households were made up of individuals and 9.6% had someone living alone who was 65 years of age or older. The average household size was 2.00 and the average family size was 2.76.

In the city the population was spread out with 13.3% under the age of 18, 21.2% from 18 to 24, 38.6% from 25 to 44, 17.8% from 45 to 64, and 9.2% who were 65 years of age or older. The median age was 30.5 years. For every 100 females, there were 96.1 males. For every 100 females age 18 and over, there were 94.7 males.

The median income for a household in the city was $47,979, and the median income for a family was $59,423 (these figures had risen to $58,457 and $79,533 respectively as of a 2007 estimate). Males had a median income of $43,825 versus $38,489 for females. The per capita income for the city was $31,156. About 8.7% of families and 12.9% of the population were below the poverty line, including 15.1% of those under age 18 and 12.9% of those age 65 or over.

Cambridge was ranked as one of the most liberal cities in America. Locals living in and near the city jokingly refer to it as "The People's Republic of Cambridge." For 2012, the residential property tax rate in Cambridge is $8.48 per $1,000. Cambridge enjoys the highest possible bond credit rating, AAA, with all three Wall Street rating agencies.

Cambridge is noted for its diverse population, both racially and economically. Residents, known as Cantabrigians, include affluent MIT and Harvard professors. The first legal applications in America for same-sex marriage licenses were issued at Cambridge's City Hall.

Cambridge is also the birthplace of Thai king Bhumibol Adulyadej (Rama IX), who is the world's longest reigning monarch at age 82 (2010), as well as the longest reigning monarch in Thai history. He is also the first king of a foreign country to be born in the United States.