“Washington, DC is 12 square miles bordered by reality” is a statement about the United States capital city—“Washington” is a metonym for the federal government—that is often credited to U.S. President Andrew Johnson (1808-1875), but he never said it. Johnson was credited on the newsgroup alt.history.what-if on June 20, 1996. Washington, D.C. is 68.34 square miles, not 12 square miles.
 
American humorist Art Hoppe (1925-2000) wrote in the San Francisco (CA) Chronicle (reprinted in many other newspapers) in March 1962:
 
“Well, Washington is several miles square and about as tall, say, as the Washington Monument, give or take a little. It is surrounded on all four sides by reality.”
 
”(Deputy Secretary of HUD) Bob Wood’s definition of Washington as ten square miles surrounded by reality” was cited in a 1967 book. Robert Coldwell Wood (1923-2005) possibly originated the saying in this form. “‘Don’t get me wrong, it is just that I think of Washington as 90 square miles of dreamers, surrounded on all sides by reality,’ he (Admiral Isaac C. Kidd Jr.—ed.) said” was printed in a May 1974 newspaper.
 
A popular version involves “67 square miles.” “(Robert—ed.) Young, president of Northwest Bank of Vancouver, Wash., referred to Washington as ‘67 square miles surrounded by reality’” was printed in a March 1976 newspaper. “‘Somebody once defined Washington, D.C., as 67 square miles surrounded by reality,’ the Vice President of the United States (Walter Mondale—ed.) told the guests” was printed in the Washington (DC) Post on April 1, 1977.
   
Places such as Madison, Wisconsin (the location of the University of Wisconsin); Ithaca, New York (the location of Cornell University) and Ottawa, Ontario (capital city of Canada) have had similar descriptions.
 
[This entry was assisted by the Quote Investigator and Ben Zimmer.]
 
   
Wikipedia: Washington, D.C.
Washington, D.C., formally the District of Columbia and commonly referred to as “Washington”, “the District”, or simply “D.C.”, is the capital of the United States.
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Geography
Washington, D.C., is located in the mid-Atlantic region of the U.S. East Coast. Due to the District of Columbia retrocession, the city has a total area of 68.34 square miles (177.0 km2), of which 61.05 square miles (158.1 km2) is land and 7.29 square miles (18.9 km2) (10.67%) is water. The District is bordered by Montgomery County, Maryland, to the northwest; Prince George’s County, Maryland, to the east; and Arlington and Alexandria, Virginia, to the south and west.
 
Wikipedia: Art Hoppe
Art Hoppe (Arthur Watterson Hoppe, April 23, 1925 - February 1, 2000) was a popular columnist for the San Francisco Chronicle for more than 40 years. He was known for satirical and allegorical columns that skewered the self-important. Many columns featured whimsical characters such as expert-in-all-things Homer T. Pettibone and a presidential candidate named Nobody. Occasionally, Hoppe reined in his humor for poignant columns on serious topics, such as “To Root Against Your Country,” a noted 1971 column against the Vietnam War.
 
Wikipedia: Robert Coldwell Wood
Robert Coldwell Wood (September 16, 1923 – April 1, 2005) was an American political scientist, academic and government administrator, and professor of political science at MIT. From 1965 to 1969, Wood served as the Under Secretary of the Department of Housing and Urban Development under President Lyndon B. Johnson, and for two weeks as acting secretary of the department.
   
26 March 1962, The Star-News (Chula Vista, CA), “Washingtonians: That Odd Tribe” by Art Hoppe, pg. 8-B, col. 4:
Well, Washington is several miles square and about as tall, say, as the Washington Monument, give or take a little. It is surrounded on all four sides by reality.
 
3 December 1962, Huntsville (AL) Times, “Defense in a Realistic World” (editorial), pg. 4, col. 1:
THE PENTAGON, it has been said, is a building surrounded on five sides by reality.
 
Google Books
The Department of Housing and Urban Development
By John B. Willmann
New York, NY: Praeger
1967
Pg. 117:
“We have a significant, difficult-to-define job to do in intergovernmental relations,” Beckman has commented. “We try to keep our feet on the ground by recalling from time to time (Deputy Secretary of HUD) Bob Wood’s definition of Washington as ten square miles surrounded by reality.”
 
19 May 1974, Dallas (TX) Morning News, “Soviets Seek No. 1 at Sea, Kidd Says” by Robert Finklea, pg. 11A, col. 4:
“Don’t get me wrong, it is just that I think of Washington as 90 square miles of dreamers, surrounded on all sides by reality,” he (Admiral Isaac C. Kidd Jr.—ed.) said.
 
Old Fulton NY Post Cards
20 March 1975, Smithtown (NY) News, “No Room For Reality” by Bernard Paley, pg. 4, col. 2:
The nation’s capital has been described as an enclave surrounded on four sides by reality.
 

REMARKS OF SENATOR HUBERT H. HUMPHREY
COLLEGE OF ST. THOMAS
St. Paul, Minnesota
February 23, 1976
It can be said that Washington is a city of some 750,000 people, bounded on four sides by reality.  “http://www2.mnhs.org/library/findaids/00442/pdfa/00442-03903.pdf
REMARKS OF SENATOR HUBERT H. HUMPHREY
COLLEGE OF ST. THOMAS
St. Paul, Minnesota
February 23, 1976
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It can be said that Washington is a city of some 750,000 people, bounded on four sides by reality. 
 
8 March 1976, St. Louis (MO) Post-Dispatch, “Brinkley Gibes At Politicians,” pg. 4A, col. 5:
“Washington has been described—accurately, I think—as 10 square miles surrounded on all sides by reality,” said Brinkley, who was once dubbed by a colleague “David of the devastating quip.”
 
31 March 1976, Muncie (IN) Evening Press, “Banks’ image ailing, bankers told,” pg. 16, col. 2:
(Robert—ed.) Young, president of Northwest Bank of Vancouver, Wash., referred to Washington as “67 square miles surrounded by reality.”
 
HathiTrust Digital Library
November 1976, Journal of Home Economics, “Government Policy, Stress, and the Family” by U.S. Senator Walter F. Mondale, pg. 11, col. 1:
Someone once said that the nation’s capital consists of 17 square miles surrounded by reality.
 
21 April 1977, Washington (DC) Post, “A Meeting of Diplomatic Travelers” by Donnie Radcliffe, pg. E5:
“Somebody once defined Washington, D.C., as 67 square miles surrounded by reality,” the Vice President of the United States (Walter Mondale—ed.) told the guests, once they had picked clean their delicate squab and had daintily tested their fingerbowls.
 
6 August 1977, Pensacola (FL) Journal, “Democratic Party Chief Drops in to ‘Say Hello’” by Jim Norman, pg. 1B, col. 2:
He (Ken Curtis, chairman of the Democratic National Committee—ed.) emphasized his belief that party officials have to stay in contact with the grass-roots Democrats by quoting VIce President Walter Mondale’s statement that “Washington is 67 square miles surrounded by reality.”
 
18 January 1981, The Sunday Oregonian (Portland, OR), “In one ear: Blazers give jazz man something to toot about” by Rod Patterson, Sunday sec., pg. 2, col. 6:
David (Brinkley, of NBC News—ed.) said the trip to Portland was a pleasure because it gave him the chance to get out of Washington, D.C., “a city of 70 square miles surrounded by reality.”
 
21 May 1982, Huntsville (AL) Times, “Homebuilders Face ‘Year of Survival,’ President Believes” by Vicki Reardon, pg. A-4, col. 3:
As president of the NAHB, he (Fred Napolitano of the National Association of Homebuilders—ed.) spends a great deal of his time in Washington, D.C., which he describes as “10 square miles surrounded by reality.”
 
5 July 1987, The Sun (Baltimore, MD), “Recall bid aims to oust Arizona’s ‘incredible’ governor of 6 months” by Ellen Uzelac, pg. 3A< col. 6:

“This is a Phoenix phenomenon. This is a fishbowl, just like Washington, It’s a city bordered by reality,” Mr. Davis said.
(Kurt Davis, executive director of the state Republican Party.—ed.)
   
Google Groups: alt.history.what-if
Should have let the South secede
Bydyn
6/20/96
(...)
Tim
“Washington, DC is 12 square miles bordered by reality.”
—President Johnson (Andrew, not Lyndon, Johnson) in 1865
 
Google Groups: soc.history.what-if
Have democratic nations ever fought one another?
Bydyn
9/26/96
(...)
Tim
“Washington, DC is 12 square miles bordered by reality.”
—President Johnson (Andrew, not Lyndon, Johnson) in 1865
     
Google Books
The Handbook for Exploding the Economic Myths of the Political Sound Bite
By Jim Boehm
West Conshohohocken, PA; Infinity Publishing Company
2006
Pg. 153:
“No wonder Washington, D.C. is so often described as 67 square miles surrounded by reality, an influence-peddling pleasure palace, a whorehouse where every four years we get to elect a new piano player.”
Barry Asmus
Imprimis 10.93
 
New York (NY) Times—City Room - Blogging From the Five Boroughs
Name America’s Most Liberal City
By SEWELL CHAN NOVEMBER 21, 2007 2:01 PM
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COMMENTS
Tony Mello November 21, 2007 · 3:35 pm
Madison, Wisconsin, home of the Onion Newspaper, Tammy Baldwin and University of Wisconsin has been described as “67 square miles surrounded by reality.”
 
Google Books
The American College Town
By Blake Gumprecht
Amherst, MA: University of Massachusetts Press
2008
Pg. 350:
Austin, Boulder, Cambridge, Iowa City, Ithaca, and Madison are also known as “[Insert number] square miles surrounded by reality.
 
Google Books
Freedom IS…:
A Book/Journal with a Twist
By Kathleen Wense
Victoria, BC: Trafford Publishing
2008
Pg. 191:
ANDREW JOHNSON (1865-1869) “Washington, DC is 12 square miles bordered by reality.” “I have reached the summit of my ambition.”
 
Urban Dictionary
Warshington
Washington DC—as pronounced by locals yet somehow appropriate for other reasons.
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#washington dc #67 square miles surrounded by reality #capitol #anacostia #chez whut
by England phi beta gamma May 21, 2008
 
Twitter
tonyaengst‏
@tonyaengst
Replying to @nancydavis
@nancydavis - fun article. Ithaca is also called “ten square miles, surrounded by reality.” I wish we could spread out that ten sq miles.
6:33 AM - 14 Nov 2008
 
Twitter
Shellee Hale‏
@shelleehale
“Washington, DC is 12 square miles bordered by reality.” - Andrew Johnson
11:29 AM - 7 Sep 2009
 
A Sharp Eye
“Washington, DC is 12 square miles bordered by reality.” – Andrew Johnson
JUNE 21, 2010
 
Google Books
Known and Unknown:
A Memoir
By Donald Rumsfeld
New York, NY: Sentinel (Penguin Books)
2011
Pg. ?:
“Washington, D.C. is sixty square miles surrounded by reality.” —As quoted in Rumsfeld’s Rules
 
Twitter
MJ Aherne‏
@ahernemj
MJ Aherne Retweeted
FN water & sewage could largely be cleaned up, realistically in a decade, but not with “Ottawa is 30 Sq miles surrounded by reality” dynamic https://twitter.com/ThomasLBoyce/status/791385062499491840 …
5:26 PM - 26 Oct 2016