How Google US Postal Code Abbreviations for Ancestry Research

How to use US Postal code abbreviations from different time periods in Ancestry research.

Throughout the history of the United States postal service, different abbreviations have been used to represent states. Remember, when you are doing a Google search, you will be looking for information that has been recorded during different periods. You will want to account for possible variations in your search query. For example, the US postal code abbreviations over time for Colorado are as follows: 1874 Colo., 1963 CO. If I were developing a search query and was looking for information about a person in a specific location, I would do the following:

Simple query: “Ora Jones” “Co” OR “Colo.”
Query to search for multiple name variations: “Ora Jones” OR “Ora * Jones” OR “Jones, Ora” genealogy OR ancestry Colorado OR “CO” OR “Colo.”

US Postal Code Abbreviations for States/Territories

	1831	1874	1943	Jun-63	Oct-63
Alabama	AL	Ala.	Ala.	ALA	AL
Alaska	—	Alaska	Alaska	ALSK	AK
Arizona	—	Ariz.	Ariz.	ARIZ	AZ
Arkansas	Ar. T.	Ark.	Ark.	ARK	AR
California	—	Cal.	Calif.	CALIF	CA
Colorado	—	Colo.	Colo.	COL	CO
Connecticut	Ct.	Conn.	Conn.	CONN	CT
Delaware	De.	Del.	Del.	DEL	DE
District of Columbia	D. C.	D. C.	D. C.	DC	DC
Florida	Fl. T.	Fla.	Fla.	FLA	FL
Georgia	Ga.	Ga.	Ga.	GA	GA
Hawaii	—	—	Hawaii	HAW	HI
Idaho	—	Idaho	Idaho	IDA	ID
Illinois	Il.	Ill.	Ill.	ILL	IL
Indiana	Ia.	Ind.	Ind.	IND	IN
Iowa	—	Iowa	Iowa	IOWA	IA
Kansas	—	Kans.	Kans.	KANS	KS
Kentucky	Ky.	Ky.	Ky.	KY	KY
Louisiana	La.	La.	La.	LA	LA
Maine	Me.	Me.	Maine	ME	ME
Maryland	Md.	Md.	Md.	MD	MD
Massachusetts	Ms.	Mass.	Mass.	MASS	MA
Michigan	Mic. T.	Mich.	Mich.	MICH	MI
Minnesota	—	Minn.	Minn.	MINN	MN
Mississippi	Mi.	Miss.	Miss.	MISS	MS
Missouri	Mo.	Mo.	Mo.	MO	MO
Montana	—	Mont.	Mont.	MONT	MT
Nebraska	—	Nebr.	Nebr.	NEB	NB *
Nevada	—	Nev.	Nev.	NEV	NV
New Hampshire	N. H.	N. H.	N. H.	NH	NH
New Jersey	N. J.	N. J.	N. J.	NJ	NJ
New Mexico	—	N. Mex.	N. Mex.	NM	NM
New York	N. Y.	N. Y.	N. Y.	NY	NY
North Carolina	N. C.	N. C.	N. C.	NC	NC
North Dakota	—	—	N. Dak.	ND	ND
Ohio	O.	Ohio	Ohio	OHIO	OH
Oklahoma	—	—	Okla.	OKLA	OK
Oregon	—	Oreg.	Oreg.	ORE	OR
Pennsylvania	Pa.	Pa.	Pa.	PA	PA
Puerto Rico	—	—	P. R.	PR	PR
Rhode Island	R. I.	R. I.	R. I.	RI	RI
South Carolina	S. C.	S. C.	S. C.	SC	SC
South Dakota	—	—	S. Dak.	SD	SD
Tennessee	Te.	Tenn.	Tenn.	TENN	TN
Texas	—	Tex.	Tex.	TEX	TX
Utah	—	Utah	Utah	UTAH	UT
Vermont	Vt.	Vt.	Vt.	VT	VT
Virginia	Va.	Va.	Va.	VA	VA
Washington	—	Wash.	Wash.	WASH	WA
West Virginia	—	W. Va.	W. Va.	W VA	WV
Wisconsin		Wis.	Wis.	WIS	WI
Wyoming	—	Wyo.	Wyo.	WYO	WY

Sources: 1831, Table of Post Offices in the United States; 1874 and 1943, United States Official Postal Guide; 6/1963, Postal Bulletin 20368; 10/196.

*To date, only one change has been made to the abbreviations issued in October 1963. In November 1969, at the request of the Canadian postal administration, the abbreviation for Nebraska, originally NB, was changed to NE, to avoid confusion with New Brunswick in Canada

History of United States Postal Codes

Until 1963 the Post Office Department preferred that state and territorial names be written out in full to avoid confusion but accepted the widespread public practice of abbreviation. The Department published lists of preferred state abbreviations in the 1831 Table of Post Offices in the United States and in the United States Official Postal Guide, first published in 1874. Most of the preferred abbreviations in 1874 remained the same for nearly the next 90 years.

On July 1, 1963, the Post Office Department implemented the five-digit ZIP Code, which was placed after the state name in the last line of an address. To provide room for the new code in the address line, the Department published an initial list of state abbreviations in the June 27, 1963, issue of the Postal Bulletin. Many of these initial abbreviations consisted of four letters.

Four months later, in October 1963, the Department published the now-familiar list of two-letter state abbreviations in Publication 59, Abbreviations for Use with ZIP Code. Two-letter abbreviations were:

. . . provided by the Post Office Department as an aid to mailers in accommodating ZIP Codes within the usual City-State line of addresses.

The abbreviations are based on a maximum 23-position line, because this has been found to be the most universally acceptable line capacity basis for major addressing systems.

The implementation of two-letter state abbreviations was gradual; initially they were intended for optional use only by large business mailers in conjunction with ZIP Codes.

To date, only one change has been made to the abbreviations issued in October 1963. In November 1969, at the request of the Canadian postal administration, the abbreviation for Nebraska, originally NB, was changed to NE, to avoid confusion with New Brunswick in Canada