According to the USGS, Bostonia is located at . This is near the intersection of North 2nd Street and Broadway in the city of El Cajon. Bostonia Street, the Bostonia Post Office, the former Bostonia Ballroom, Bostonia Elementary School and the Bostonia Fire Station are all within of this location and all, except the fire station, are within the city of El Cajon. This is the area identified on most maps as Bostonia. However, the census-designated place of Bostonia is entirely outside the city limits of El Cajon, in an unincorporated area of County. The CDP comprises most of unincorporated El Cajon north of Broadway and east of State Route 67, and a small area west of State Route 67. Mail sent to all parts of Bostonia is addressed to El Cajon. According to the United States Census Bureau Bostonia is located at . This is approximately one mile northwest of where the USGS places Bostonia, near the geographic center of the CDP. The CDP has a total area of, all land.
Demographics
The statistics below include only the census-designated place, not the part of Bostonia within the city limits of El Cajon.
2010
At the 2010 census Bostonia had a population of 15,379. The population density was 7,973.4 people per square mile. The racial makeup of Bostonia was 10,891 White, 1,011 African American, 102 Native American, 375 Asian, 89 Pacific Islander, 1,781 from other races, and 1,130 from two or more races. Hispanic or Latino of any race were 3,941 persons. The census reported that 15,272 people lived in households, 55 lived in non-institutionalized group quarters, and 52 were institutionalized. There were 5,573 households, 2,028 had children under the age of 18 living in them, 2,381 were opposite-sex married couplesliving together, 976 had a female householder with no husband present, 405 had a male householder with no wife present. There were 416 unmarried opposite-sex partnerships, and 47 same-sex married couples or partnerships. 1,338 households were one person and 545 had someone living alone who was 65 or older. The average household size was 2.74. There were 3,762 families ; the average family size was 3.25. The age distribution was 3,813 people under the age of 18, 1,820 people aged 18 to 24, 4,157 people aged 25 to 44, 3,832 people aged 45 to 64, and 1,757 people who were 65 or older. The median age was 33.8 years. For every 100 females, there were 94.6 males. For every 100 females age 18 and over, there were 90.9 males. There were 5,893 housing units at an average density of 3,055.3 per square mile, of the occupied units 2,342 were owner-occupied and 3,231 were rented. The homeowner vacancy rate was 2.9%; the rental vacancy rate was 5.5%. 6,071 people lived in owner-occupied housing units and 9,201 people lived in rental housing units.
2000
At the 2000 census there were 15,169 people, 5,640 households, and 3,778 families in the CDP. The population density was 7,810.2 inhabitants per square mile. There were 5,819 housing units at an average density of 2,996.1 per square mile. The racial makeup of the CDP was 79.81% White, 3.98% African American, 0.90% Native American, 1.48% Asian, 0.36% Pacific Islander, 7.79% from other races, and 5.68% from two or more races. Hispanic or Latino of any race were 16.63%. Of the 5,640 households 37.0% had children under the age of 18 living with them, 47.0% were married couples living together, 14.2% had a female householder with no husband present, and 33.0% were non-families. 24.3% of households were one person and 10.5% had someone living alone who was 65 years of age or older. The average household size was 2.67 and the average family size was 3.19. The age distribution was 28.3% under the age of 18, 10.7% from 18 to 24, 31.8% from 25 to 44, 17.7% from 45 to 64, and 11.6% who were 65 years of age or older. The median age was 32 years. For every 100 females there were 96.2 males. For every 100 females age 18 and over, there were 91.9 males. The median household income was $37,148 and the median family income was $41,727. Males had a median income of $32,240 versus $26,335 for females. The per capita income for the CDP was $17,328. About 9.1% of families and 12.5% of the population were below the poverty line, including 14.9% of those under age 18 and 7.4% of those age 65 or over.
