Harmony is a small town located on the western edge of the Grand Senora Desert, on the border of Los Santos County and Blaine County. It is located west of Sandy Shores, northwest of Bolingbroke Penitentiary, and southwest of the Alamo Sea. Route 68 is the main route running through the town and contains all of the local businesses. Harmony's economy mainly comes from being used as a rest stop, which is why there are two convenience stores right next to each other. A Dollar Pills pharmacy and an RV dealership are located in the area.

Harmony is divided into two sections: west Harmony and east Harmony. The western side of Harmony is more residential and contains a large trailer park, along with the pharmacy and a Discount Store clothing store. The eastern side of Harmony is meant for business and commerce. Most of the stores in Harmony are located here, which include a Los Santos Customs garage and a Fleeca bank. Sandy Shores Airfield is also located nearby.