List of cities from UNION's county

ALCESTER	ALSEN
BERESFORD	BIG SPRINGS
DAKOTA DUNES	ELK POINT
EMMET	JEFFERSON
JUNCTION CITY	MCCOOK LAKE
N SIOUX CITY	NORA
NORTH SIOUX CITY	RICHLAND
SPINK

What is ZIP Code?

ZIP codes are a system of postal codes used by the United States Postal Service (USPS) since 1963. The term ZIP, an acronym for Zone Improvement Plan,[1] is properly written in capital letters and was chosen to suggest that the mail travels more efficiently, and therefore more quickly, when senders use the code in the postal address. The basic format consists of five decimal numerical digits. An extended ZIP+4 code, introduced in the 1980s, includes the five digits of the ZIP code, a hyphen, and four more digits that determine a more precise location than the ZIP code alone. The term ZIP code was originally registered as a servicemark (a type of trademark) by the U.S. Postal Service, but its registration has since expired