Arlington is a community about seven miles southwest of Riverside, California, that is part of the Inland Empire, which is east of the Los Angeles and Orange County metropolitan areas. With a population of about 12,300, the major commercial hub of Arlington is centered on Magnolia Avenue, a major east-west thoroughfare that connects the …Arlington is a community about seven miles southwest of Riverside, California, that is part of the Inland Empire, which is east of the Los Angeles and Orange County metropolitan areas. With a population of about 12,300, the major commercial hub of Arlington is centered on Magnolia Avenue, a major east-west thoroughfare that connects the community with Downtown Riverside to the east and the Corona area to the west.