Somerville has a mix of blue collar families, who tend to be concentrated in the area known as East Somerville, and college students and young professionals, many of whom live in sections that border Cambridge's Harvard Square and Porter Square and Medford's Tufts University.

Somerville also has a number of squares that are bustling business and entertainment centers, among them Davis Square, Union Square, Ball Square and Magoun Square.

Somerville is located at 42°23'26" North, 71°6'13" West (42.390546, -71.103683)^{1}.

According to the United States Census Bureau, the city has a total area of 10.9 km² (4.2 mi²). 10.6 km² (4.1 mi²) of it is land and 0.3 km² (0.1 mi²) of it is water. The total area is 2.61% water.

As of the census of 2000, there are 77,478 people, 31,555 households, and 14,673 families residing in the city. The population density is 7,278.4/km² (18,868.1/mi²). There are 32,477 housing units at an average density of 3,051.0/km² (7,909.1/mi²). The racial makeup of the city is 76.97% White, 6.50% African American, 0.22% Native American, 6.44% Asian, 0.06% Pacific Islander, 4.96% from other races, and 4.85% from two or more races. 8.76% of the population are Hispanic or Latino of any race.

There are 31,555 households out of which 18.8% have children under the age of 18 living with them, 32.2% are married couples living together, 10.3% have a female householder with no husband present, and 53.5% are non-families. 31.0% of all households are made up of individuals and 8.8% 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 3.06.

In the city the population is spread out with 14.8% under the age of 18, 15.9% from 18 to 24, 42.6% from 25 to 44, 16.2% from 45 to 64, and 10.5% who are 65 years of age or older. The median age is 31 years. For every 100 females there are 94.9 males. For every 100 females age 18 and over, there are 93.2 males.

The median income for a household in the city is $46,315, and the median income for a family is $51,243. Males have a median income of $36,333 versus $31,418 for females. The per capita income for the city is $23,628. 12.5% of the population and 8.4% of families are below the poverty line. Out of the total people living in poverty, 14.3% are under the age of 18 and 13.6% are 65 or older.