Area code 231 is used for the following cities:
Click on any city to see time zone and surise sunset time.
- Germany - North Rhine-Westphalia - Dortmund (+49-231)
- Guyana - Georgetown (+592-231)
- India - Maharashtra - Kolhapur (+91-231)
- USA - Michigan - Acme (+1-231)
- USA - Michigan - Aetna Township-Mecosta (+1-231)
- USA - Michigan - Almira Township (+1-231)
- USA - Michigan - Amber Township (+1-231)
- USA - Michigan - Bear Creek Township (+1-231)
- USA - Michigan - Benton Township (+1-231)
- USA - Michigan - Big Rapids (+1-231)
- USA - Michigan - Blair Township (+1-231)
- USA - Michigan - Brooks Township (+1-231)
- USA - Michigan - Cadillac (+1-231)
- USA - Michigan - Charlevoix (+1-231)
- USA - Michigan - Cheboygan (+1-231)
- USA - Michigan - Dalton Township (+1-231)
- USA - Michigan - East Bay Township (+1-231)
- USA - Michigan - East Jordan (+1-231)
- USA - Michigan - Egelston Township (+1-231)
- USA - Michigan - Ellis Township (+1-231)
- USA - Michigan - Elmira Township (+1-231)
- USA - Michigan - Elmwood Charter Township (+1-231)
- USA - Michigan - Evart (+1-231)
- USA - Michigan - Frankfort (+1-231)
- USA - Michigan - Fremont (+1-231)
- USA - Michigan - Fruitland Township (+1-231)
- USA - Michigan - Fruitport Charter Township (+1-231)
- USA - Michigan - Grant (+1-231)
- USA - Michigan - Green Charter Township (+1-231)
- USA - Michigan - Green Lake Township (+1-231)
- USA - Michigan - Hamlin Township-Mason (+1-231)
- USA - Michigan - Hart (+1-231)
- USA - Michigan - Highland Township-Osceola (+1-231)
- USA - Michigan - Holland Charter Township (+1-231)
- USA - Michigan - Holton Township (+1-231)
- USA - Michigan - Kalkaska Township (+1-231)
- USA - Michigan - Lake City (+1-231)
- USA - Michigan - Laketon Township (+1-231)
- USA - Michigan - Long Lake Township (+1-231)
- USA - Michigan - Ludington (+1-231)
- USA - Michigan - Mancelona Township (+1-231)
- USA - Michigan - Manistee (+1-231)
- USA - Michigan - Manistee Township (+1-231)
- USA - Michigan - Manton (+1-231)
- USA - Michigan - McBain (+1-231)
- USA - Michigan - Montague (+1-231)
- USA - Michigan - Morton Township (+1-231)
- USA - Michigan - Muskegon (+1-231)
- USA - Michigan - Muskegon Heights (+1-231)
- USA - Michigan - Newaygo (+1-231)
- USA - Michigan - North Muskegon (+1-231)
- USA - Michigan - Norton Shores (+1-231)
- USA - Michigan - Oakfield Township (+1-231)
- USA - Michigan - Paradise Township (+1-231)
- USA - Michigan - Peninsula Township (+1-231)
- USA - Michigan - Petoskey (+1-231)
- USA - Michigan - Reed City (+1-231)
- USA - Michigan - Reynolds Township (+1-231)
- USA - Michigan - Roosevelt Park (+1-231)
- USA - Michigan - Scottville (+1-231)
- USA - Michigan - Shelby Township (+1-231)
- USA - Michigan - Traverse City (+1-231)
- USA - Michigan - White Cloud (+1-231)
- USA - Michigan - Whitehall (+1-231)
- USA - Michigan - Wolf Lake (+1-231)