The Best Southwest is a term commonly applied to four Dallas suburbs – Cedar Hill, DeSoto, Duncanville, and Lancaster – in southwestern Dallas County, Texas (USA). As of the 2010 census, the four suburbs had a combined population of 168,960. The term "Best Southwest" was first used when the Cedar Hill, DeSoto, Duncanville, and Lancaster chambers of commerce formed a partnership to improve cooperation between the cities. They formed the Best Southwest Chamber Partnership in 1986, and it was incorporated in 1990.