PHILADELPHIA SECTION BOUNDARIES OVER THE YEARS

	Philadelphia Section Boundaries 1978-1980 Once National started using ZIP Codes to define its boundaries, the Philadelphia boundaries were descriped by the ZIP Codes 170-171, 174-176, 180-181, 189-193, 197-198.
	Philadelphia Section Boundaries 1980-1999 The Lehigh Valley Section was chartered in 1980. This reduced the Philadelphia Section boundaries to ZIP Codes 170-171, 173-176, 189-194, 197-198. In 1984, ZIP Code 173 was added to our section after the National ZIP Code committee had performed a boundary analysis and verification.
	Philadelphia Section Boundaries 1999-Present Again in 1999, the Philadelphia Section boundaries were reduced when the DelMar Peninsula Section was chartered. Current ZIP Code boundaries are 170-171, 173-176, 189-194. At no point in time has the Philadelphia Section held boundaries in New Jersey. The section does have many members that live in New Jersey and offically made the Philadelphia Section their choice.

With the inception of the use of ZIP Codes by the U.S. Postal Service for the delivery of mail across the country, SWE section boundaries became defined by the ZIP Codes associated with previous verbal descriptions of the areas. For ease in tabulations, only the first three digits were used in most cases. In some cases, this simplification resulted in difficulties for some sections to have an accurate definition of their geographical area and seven-digit numbers had to be used in some cases. However, in general, the three-digit codes provide an overview of the area.

Three-digit ZIP Codes are the first three digits of a group of ZIP Codes that share a mail sorting/distribution center. National has choosen to use three-digit ZIP Codes to define the boundaries of its sections. In the above maps, three-digit ZIP Codes are shown in the red lines. Collectively these lines make up the Philadelphia Section Boundaries.

Sources:
SWE National Section ZIP Code Boundaries Lists Dated: June 30, 1978, January 15, 1985, and July 13, 2006.