As of the censusGR2 of 2000, there were 36,929 people, 13,502 households, and 9,086 families residing in the city. The population density was 1,037.0/km² (2,686.5/mi²). There were 13,957 housing units at an average density of 391.9/km² (1,015.3/mi²). The racial makeup of the city was 62.92% White, 8.67% African American, 0.87% Native American, 7.02% Asian, 0.13% Pacific Islander, 15.61% from other races, and 4.77% from two or more races. Hispanic or Latino of any race were 35.24% of the population.
There were 13,502 households out of which 35.4% had children under the age of 18 living with them, 46.4% were married couples living together, 15.4% had a female householder with no husband present, and 32.7% were non-families. 26.0% of all households were made up of individuals and 8.8% had someone living alone who was 65 years of age or older. The average household size was 2.71 and the average family size was 3.29.
In the city the population was spread out with 27.4% under the age of 18, 8.0% from 18 to 24, 34.0% from 25 to 44, 20.2% from 45 to 64, and 10.4% who were 65 years of age or older. The median age was 34 years. For every 100 females there were 92.2 males. For every 100 females age 18 and over, there were 87.6 males.
The median income for a household in the city was $45,375, and the median income for a family was $49,703. Males had a median income of $41,039 versus $32,259 for females. The per capita income for the city was $21,686. About 9.7% of families and 13.1% of the population were below the poverty line, including 18.3% of those under age 18 and 9.7% of those age 65 or over.
Monrovia is the fourth oldest general law city in Los Angeles County and the L.A. Basin. Established in 1887 as an incorporated city, Monrovia has grown from a sparse community of orange ranches to a residential community of 37,000 residents. People traveling between Los Angeles and San Bernardino traveled "via Monroe's Ranch," hence the name.
Around 500 BC, a band of Shoshonean-speaking Indians established settlements in what is now the San Gabriel Valley. These native Americans came to be called the Gabrieliño Indians by early Spanish explorers, and are now referred to as the Tongva. The Tongva did not practice agriculture, but instead relied upon the wild seeds, berries, and plants that grew near the rivers and marshlands. Since the San Gabriel Valley area was home to large numbers of oak trees, such as Coast Live Oak, and Interior Live Oak, a staple of the Tongva diet was an acorn mush made by boiling acorn flour.
Monrovia's history with Europeans dates back to 1769, when all land in California was claimed by the King of Spain. The first Europeans visited the San Gabriel Valley, including Monrovia, during a 1769 expedition from San Diego to Monterey Bay commanded by Don Gaspar Portola. Accompanying Portola was a Franciscan Father from Father Junipero Serra's Franciscan order of Mexico, Juan Crespi, who served as the diarist of the expedition. Much of what is known of early California is known only from the detailed descriptions recorded by Crespi.
In 1771, the Franciscans established the Mission San Gabriel Arcangel in the San Gabriel Valley. The mission was a resting point for early California travelers and gathered most of the native Tongva into an agricultural lifestyle. Following the Mexican Revolution in 1839, the mission lands were nationalized.
In 1841, California Governor Juan Alvarado gave Rancho Azusa de Duarte to Andres Duarte, a Mexican soldier, and he gave Rancho Santa Anita to Hugo Reid, a naturalized Mexican citizen of American birth. Monrovia is made of parts of these two ranchos.
In the mid-1800s, most of Rancho Azusa de Duarte was subdivided and sold by Duarte to settle his debts. Some of those parcels would eventually end up as part of the ranch of William N. Monroe, Monrovia's namesake.
Rancho Santa Anita changed hands several times before the famous multimillionaire, silver baron and rancher, E.J. "Lucky" Baldwin acquired it in 1875. That same year his Los Angeles Investment Company began subdividing and selling parcels from many of his ranchos. In 1883, 240 acres (970,000 m²) of Rancho Santa Anita were sold to Monroe for $30,000. Additional parcels of Rancho Santa Anita were sold to Edward F. Spence, John D. Bicknell, James F. Crank, and J.F. Falvey.
The completion of the Santa Fe (which would run through Monrovia) and Southern Pacific railroads to Southern California would bring new people looking for homes and investment opportunities. With this in mind, Monroe, Spence, Bicknell, Crank, and Falvey decided to combine their land under the business name of the Monrovia Land and Water Company in 1886. The combined lots formed the Town of Monrovia Subdivision. The original borders of the Town of Monrovia Subdivision were Canyon Blvd. to the east, Walnut Ave. to the south, Magnolia Ave. to the west, and Lime Ave. to the north. The subdivision was then itself quickly subdivided into 600 50 by 160 foot lots and sold. Some lucky buyers of these lots turned around and sold them very quickly. Those who chose to hold on to their property saw its value fall to a fraction of its 1886-1887 value.
The town was incorporated in 1887 under the leadership of prohibitionists who wished to control the arrival of an unwelcome saloon. The first order of business for the newly formed government was to pass a tippler's law, prohibiting the sale of alcohol.
In 1903 the Monrovia News was established. In the same year, the Pacific Electric was opened providing transportation to and from Los Angeles, making it possible for Monrovians to work in Los Angeles and have their homes in Monrovia.
In 1905 Carnegie funds became available and with the help of the Board of Trade (forerunner to the Chamber of Commerce), and the Monrovia Women's Club, a bond issue was passed to purchase the Granite Bank Building to be used as a City Hall, and to acquire property for a public park. The Granite Building serves as the city hall, fire and police department facilities in 1961 and the fire department in 1974. In 1956, the old Carnegie library building was torn down and the present library constructed. The library now boasts a book collection of 95,000 volumes.As of March 2007, the city's residents were asked to vote on a new, upgraded library which is ADA-compliant and has twice as much room for books and computer usage as the current one(the measure passed with at least 70% of the vote.).
A city council-manager type government was instituted in 1923.
Monrovia has been used extensively for filming many TV shows, movies and commercials.
The CBS-TV drama "Picket Fences" was filmed throughout Monrovia. This included use of Monrovia City Hall as the fictional Rome, Wisconsin Sheriff's Office and the nearby United Methodist Church used as the Logan County Courthouse. To this day, CBS insists that the city of Rome, Wisconsin was a fictional town, although there are two actual cities in Wisconsin that bear that name.
Monrovia operates it's own Fire & Police Department's led by Fire Chief Christopher Donovan and Chief of Police Roger W. Johnson
Various wildlife ranging from deers to black bears even the occasional mountain lion can be seen roaming in Monrovia's foothill's. Monrovia's wildlife population gained notoriety in 1994 when a black bear was seen enjoying dips in northern Monrovia resident's hot tubs and swimming pools. The bear became a local celebrity to Monrovia residents after his falling ill due to his consuming a plastic grocery bag. After capture the bear was originally scheduled to be euthanized, however due to public outcry this did not happen. Instead, Samson was relocated to the Orange County Zoo where he had his own exhibit funded by monetary donations from all over the world, many of which came from school children. Samson lived at the zoo until his death from old age on May 14th 2001. A monument to Samson "The Hot Tub" Bear can be seen at the entrance to the Nature Center of Monrovia's Canyon Park.
In 1927, Patrick McDonald opened a simple restaurant at the old Monrovia Airport (where hamburgers were only ten cents, and all-you-can-drink orange juice was only five cents); the restaurant remained at the airport until 1948, when he and his then-teenage sons, Maurice and Richard, moved the entire building to San Bernardino at the corner of 14th and E Streets. In 1955, malted-shake-machine entrepreneur Ray Kroc pressured the McDonald family into selling out to him, thus denying historians the truth of the real but humble beginnings of what's now the McDonalds Corporation. To this day, McDonalds insists that Kroc started the company in San Bernardino in 1955 (moving it to the Chicago suburb of Oak Brook in the late 1960s), but most long-time Monrovia residents know better.
Monrovia High School gained a highly creditable rating in its early history. The first school in Monrovia was built in 1887. It was located where Monroe School now stands, and housed the entire elementary and high school student body. A new high school on the property now occupied by Clifton Middle School was erected in 1905, and in 1912 was greatly expanded by the addition of new buildings. In 1928 a high school to serve the communities of Arcadia, Monrovia and Duarte was built. The same structure now serves only Monrovia students, as the elementary and high school district were unified into one district in 1961. The district now has one high school, one continuation school, two middle schools and five elementary schools, and is part of the Citrus Community College District. There are also three parochial schools in Monrovia.