From Wikipedia, on demographics:
The racial makeup of the city was 47.8% White,[20] 8.5% Black or African American, 3.1% Asian, 1.1% Native American, 0.09% Pacific Islander, 33.6% from other races, and 5.9% were multiracial. In addition, 62.1% of residents identified as Hispanic or Latino (of any race), which includes 18.2% Salvadoran, 12.7% Puerto Rican, 8.4% Honduran, 7.3% Guatemalan, 2.8% Mexican, 2.2% Dominican, 0.5% Cuban, 0.5% Costa Rican, 0.4% Nicaraguan, 0.4% Panamanian, 1.4% other Central American countries, 2.5% other South American countries, 5.3% other Hispanic/Latino.[21]
The population was spread out with 27.3 under the age of 18, 10.6% from 18 to 24, 34.6% from 25 to 44, 16.3% from 45 to 64, and 11.2% who were 65 years of age or older. The median age was 31 years.
Chelsea is also VERY densely populated.