The area known as Bonsall was originally called Mount Fairview and had a post office by that name from December 28, 1871, to December 28, 1880. It received a post office in 1881 under the name Osgood, after California Southern Railroad chief engineer Joseph O. Osgood; the renaming was supposedly an unsuccessful attempt to convince Osgood to build the railroad through the San Luis Rey River valley. Following a contest, the town was renamed Bonsall in 1890, after local minister James A. Bonsall.
At the 2010 census Bonsall had a population of 3,982. The population density was 293.5 people per square mile. The racial makeup of Bonsall was 3,194 White, 67 African American, 28 Native American, 138 Asian, 10 Pacific Islander, 376 from other races, and 169 from two or more races. Hispanic or Latino of any race were 893 people. The census reported that 3,967 people lived in households, 15 lived in non-institutionalized group quarters, and no one was institutionalized. There were 1,542 households, 451 had children under the age of 18 living in them, 873 were opposite-sex married couples living together, 150 had a female householder with no husband present, 62 had a male householder with no wife present. There were 93 unmarried opposite-sex partnerships, and 12 same-sex married couples or partnerships. 337 households were one person and 109 had someone living alone who was 65 or older. The average household size was 2.57. There were 1,085 families ; the average family size was 2.99. The age distribution was 844 people under the age of 18, 278 people aged 18 to 24, 913 people aged 25 to 44, 1,262 people aged 45 to 64, and 685 people who were 65 or older. The median age was 44.1 years. For every 100 females, there were 96.7 males. For every 100 females age 18 and over, there were 98.6 males. There were 1,683 housing units at an average density of 124.0 per square mile, of the occupied units 1,112 were owner-occupied and 430 were rented. The homeowner vacancy rate was 2.6%; the rental vacancy rate was 4.2%. 2,815 people lived in owner-occupied housing units and 1,152 people lived in rental housing units.
2000
At the 2000 census there were 3,401 people, 1,285 households, and 947 families in the CDP. The population density was 252.4 inhabitants per square mile. There were 1,357 housing units at an average density of 100.7 per square mile. The racial makeup of the CDP was 84.00% White, 0.85% African American, 0.38% Native American, 2.76% Asian, 0.12% Pacific Islander, 9.73% from other races, and 2.15% from two or more races. Hispanic or Latino of any race were 21.43%. Of the 1,285 households 28.3% had children under the age of 18 living with them, 62.6% were married couples living together, 8.1% had a female householder with no husband present, and 26.3% were non-families. 19.8% of households were one person and 7.5% were one person aged 65 or older. The average household size was 2.65 and the average family size was 3.02. The age distribution was 23.2% under the age of 18, 7.1% from 18 to 24, 26.1% from 25 to 44, 27.1% from 45 to 64, and 16.5% 65 or older. The median age was 41 years. For every 100 females, there were 99.6 males. For every 100 females age 18 and over, there were 100.7 males. The median household income was $60,625 and the median family income was $61,761. Males had a median income of $43,250 versus $29,688 for females. The per capita income for the CDP was $35,942. About 6.5% of families and 6.5% of the population were below the poverty line, including 7.4% of those under age 18 and 6.0% of those age 65 or over.
In the California State Legislature, Bonsall is in, and in. In the United States House of Representatives, Bonsall is in. In June 1988, Bonsall-area voters defeated a ballot initiative to create a Community Services District after opponents argued that the boundaries included too many county taxpayers who more closely associated with neighboring cities Vista and Fallbrook rather than the unincorporated Bonsall community.
