 Ralston, a city in south-central Douglas County surrounded by Omaha on three sides and roughly bounded by 72nd to the east, 84th to the west, L on the north, and Harrison on the south.Elkhorn, on the outskirts of western Omaha and annexed in 2007; Millard, a broad area of southwest Omaha and annexed in 1971.Chalco, an unincorporated area southwest of Omaha in northern Sarpy County, is also widely regarded as a part of west Omaha.