Arcadia is an upper-middle class U.S. city in Los Angeles County, California, United States, and located approximately13 miles (21 km) northeast of downtown Los Angeles in the San Gabriel Valley and at the base of the San Gabriel Mountains. Arcadia is part of a cluster of cities, along with Temple City, Rosemead, Monterey Park, San Marino, and San Gabriel, in the west San Gabriel Valley with a growing Asian population. It is the site of the Santa Anita Park racetrack and home to the Los Angeles County Arboretum and Botanic Garden. As of the 2000 United States Census[update], the city had a population of 53,054. The estimated 2005 population was 56,565.[citation needed] The city is named after Arcadia, Greece.[citation needed]

Located approximately 13 miles (21 km) northeast of downtown Los Angeles, Arcadia is bordered by six other communities: Pasadena, Sierra Madre, El Monte, Irwindale, Monrovia, and Temple City.

According to the United States Census Bureau, the city has a total area of 28.8 km² (11.1 mi²). 28.4 km² (11.0 mi²) of it is land and 0.3 km² (0.1 mi²) of it (1.08%) is water.[citation needed]

As of the 2009 census, there were 55,900 people, 19,149 households, and 14,151 families residing in the city. The population density was 1,865.6/km² (4,830.0/mi²). There were 19,970 housing units at an average density of 702.2/km² (1,818.1/mi²). The racial makeup of the city was 45.58% White, 1.13% Black or African American, 0.25% Native American, 45.41% Asian, 0.08% Pacific Islander, 4.16% from other races, and 3.39% from two or more races. 10.61% of the population were Hispanic or Latino of any race.

There were 19,149 households out of which 35.2% had children under the age of 18 living with them, 57.8% were married couples living together, 11.9% had a female householder with no husband present, and 26.1% were non-families. 22.3% of all households were made up of individuals and 9.6% had someone living alone who was 65 years of age or older. The average household size was 2.74 and the average family size was 3.23.

In the city the population was spread out with 23.3% under the age of 18, 7.5% from 18 to 24, 27.2% from 25 to 44, 26.5% from 45 to 64, and 15.5% who were 65 years of age or older. The median age was 40 years. For every 100 females there were 88.7 males. For every 100 females age 18 and over, there were 84.6 males.

The median income for a household in the city is $107,877 and the median income for a family is $89,311. Males have a median income of $80,594 versus $66,138 for females. The per capita income for the city is $28,400. 2.4% of the population and 2.1% of families are below the poverty line. Out of the total people living in poverty, 2.0% are under the age of 18 and 6.1% are 65 or older.

Arcadia's beginnings go back over 3,000 years to the Tongva ("Gabrielino") Indian tribe, whose inhabitants lived in what is today Los Angeles County. Their fluid borders stretched from the San Gabriel Mountians in the north to Long Beach in the south, and from the island of Pimu (Catalina) in the west into today's San Bernardino County to the east. These people were also known as the Gabrielinos, a name taken from the Spanish San Gabriel Mission (in present-day San Gabriel, California), and under whose control these people worked during the mission period in California. One of Arcadia's settlements of these Native Americans was known as Aleupkigna (or “Aluupkenga) (McCawley, William. The First Angelinos: The Gabrielino Indians of Los Angeles. Malki Museum/Ballena Press, 1996) on what later became the Rancho Santa Anita, one of many land grants created during Mexican rule of California (1821-1848). The Tongva are still alive and well today, living in the Los Angeles area and other neighboring communities.

Originally part of "Rancho Santa Anita", and owned by San Gabriel Mission, Mayor-Domo, Claudio Lopez. It was named after a family relation named "Anita Cota", on his wife's side. In 1839, a large area of land that included the present-day borders of Arcadia was sold to a Scottish immigrant, Hugo Reid. Reid documented the Native Americans in a series of letters written in 1852 (Reid, Hugo. The Indians of Los Angeles County: Hugo Reid's Letters of 1853. Southwest Museum, 1968) and served as a delegate to the 1849 California Constitutional Convention.

The land holding changed owners several times before being acquired by the real estate speculator and notorious womanizer Elias Jackson "Lucky" Baldwin in 1875. Baldwin purchased 8,000 acres (32 km²) of Santa Anita for $200,000. Upon seeing the area, Baldwin gasped “By Gads! This is paradise!”. Upon buying the land, Lucky chose to make the area his home and immediately started erecting buildings and cultivating the land for farming, orchards and ranches. In 1885, the main line of the Santa Fe Railroad, in which Baldwin was a stockholder, was opened through the ranch, making subdivision of part of the land into a town site practical. In 1889, on a site just north of the corner of First Avenue and St. Joseph Street, adjacent to the Santa Fe tracks, Baldwin opened the 35 room Hotel Oakwood to be the centerpiece of his new town.