Pomona () is a city in Los Angeles County, California, United States. Pomona is located in the Pomona Valley, between the Inland Empire and the San Gabriel Valley. As of the 2010 United States Census, the city's population was 149,058.
The main campus of California State Polytechnic University, Pomona, also known as Cal Poly Pomona or simply as Cal Poly, lies mostly within Pomona's city limits. Some campus areas are also located in San Dimas and Walnut.
The area was originally occupied by the Tongva Native Americans.
The city is named after Pomona, the ancient Roman goddess of fruit. For horticulturist Solomon Gates, "Pomona" was the winning entry in a contest to name the city in 1875, before anyone had ever planted a fruit tree there. The city was first settled by Ricardo Vejar and Ygnacio Palomares in the 1830s, when California and much of the now-American Southwest were part of Mexico.
The first Anglo-Americans arrived in prior to 1848 when the signing of the Treaty of Guadalupe Hidalgo resulted in California becoming part of the United States. In 1864, the owners of Rancho San José sold 12,000 acres (49,000,000 m2; 49 km2) to Louis Phillips, a Jewish Prussian immigrant, who would shortly be known as "the richest man in Los Angeles County." He built the largest commercial building in Los Angeles central business district at the time, the Phillips Block, which would eventually house Hamburger's, the then-largest department store in the Western United States.
Phillips sold a parcel of his land to William "Uncle Billy" Rubottom, in 1866 who founded a new town there and named it Spadra after his hometown, now part of Clarksville, Arkansas.