Area codes 314 and 557 are telephone area codes in the North American Numbering Plan (NANP) in the U.S. state of Missouri, serving St. Louis and most of its inner-ring suburbs in neighboring St. Louis County. The numbering plan area is bordered to the west by area code 636, which serves St. Louis' outer suburbs to the west, south, and north. Across the Mississippi River to the east, 314 is adjacent to area code 618, which serves southern Illinois and most of Metro East. Area code 557 was added to the 314 numbering plan area on August 12, 2022, to form an overlay numbering plan.
Area codes 314 and 557 are telephone area codes in the North American Numbering Plan (NANP) in the U.S. state of Missouri, serving St. Louis and most of its inner-ring suburbs in neighboring St. Louis County. The numbering plan area is bordered to the west by area code 636, which serves St. Louis' outer suburbs to the west, south, and north. Across the Mississippi River to the east, 314 is adjacent to area code 618, which serves southern Illinois and most of Metro East. Area code 557 was added to the 314 numbering plan area on August 12, 2022, to form an overlay numbering plan. (en) 电话区号314覆盖圣路易斯及其邻近圣路易斯县的大部分内环郊区。它的西面完全被区号636包围，636为西、南和北圣路易斯外环郊区提供服务。横跨密西西比河向东，314与区号618接壤，618服务伊利诺伊州南部和大都会东区的大部分地区。 “314”有时被用来代表整个大圣路易斯区域。 (zh)
Area codes 314 and 557 are telephone area codes in the North American Numbering Plan (NANP) in the U.S. state of Missouri, serving St. Louis and most of its inner-ring suburbs in neighboring St. Louis County. The numbering plan area is bordered to the west by area code 636, which serves St. Louis' outer suburbs to the west, south, and north. Across the Mississippi River to the east, 314 is adjacent to area code 618, which serves southern Illinois and most of Metro East. Area code 557 was added to the 314 numbering plan area on August 12, 2022, to form an overlay numbering plan. (en) 电话区号314覆盖圣路易斯及其邻近圣路易斯县的大部分内环郊区。它的西面完全被区号636包围，636为西、南和北圣路易斯外环郊区提供服务。横跨密西西比河向东，314与区号618接壤，618服务伊利诺伊州南部和大都会东区的大部分地区。 “314”有时被用来代表整个大圣路易斯区域。 (zh)
