Glossary and Definitions ...
- Area Code Overlay
- An Overlay refers to the situation in which two (or more) area codes (eg- 304, 681) serve the same geographic area. In the case of Riverdale Estates, area code (681) is the Overlay for area code (304).
The Overlay is necessary when the geographic area requires (or expects to need) more phone numbers than can be provided by a single area code.
When an Overlay is present, 10-digit dialing becomes necessary even for local calls. There are different types of Overlays, with each of the different Overlays having its own characteristics and dialing requirements.
If you would like to learn more about Overlays, we suggest the Wikipedia entry for Overlays.
- GNIS Codes
- The function of the U.S. Board on Geographic Names (BGN) is to establish uniform names for geographic features (eg- communities, mountains, lakes, rivers, streams, etc). The BGN was created to address the problems caused by spelling and naming variations. BGN–accepted names are kept in a database called the Geographic Names Information System (GNIS), which is operated and maintained by the U.S. Geological Survey (USGS).
A unique and permanent identifier has been assigned for each feature in the GNIS database. These names and identifiers are definitive.
Riverdale Estates has been given the GNIS Feature ID of '1740782'. Click here to see the GNIS Record for Riverdale Estates.