Complex sentence: Area code 314 serves the independent city of St. Louis, Missouri and some of its suburbs in neighboring St. Louis County, most of these suburbs are to the northwest or west-central to the city's core.
Split into simpler sentences: Area code 314 serves the independent city of St. Louis, Missouri and some of its suburbs in neighboring St. Louis County. Most of these suburbs in 314 are to the northwest or west-central to the city's core.