The “Hudson River Derby” (or “New York Derby”) is a soccer match between the New York Red Bulls and the New York City Football Club (NYCFC). NYCFC was formed in 2013 and played their first games in 2015, and the first Hudson River Derby was in 2015. The two teams have played against each other more than once a year.
 
The New York Red Bulls play in Red Bull Arena in Harrison, New Jersey (about seven miles from Manhattan). The New York City Football Club plays in Yankee Stadium in the Bronx, New York. The Hudson River separates New Jersey and New York City.
 
Early citations refer to the New York Red Bulls against the New York Cosmos (a North American Soccer League team playing at the Mitchel Athletic Complex in Uniondale, Long Island). “A New York Derby: Red Bulls v. Cosmos?” was posted on Twitter by Smalrus™ on September 20, 2010. “Cosmos/Drinks in the Hudson River Derby” was posted on Twitter by Michael Heinz on January 9, 2013.
 
“There’s only one NY soccer team to me, the Red Bulls. But seriously I can’t wait for the New York Derby to happen. #NYCFC” was posted on Twitter by Knud G. Ferdinand on May 21, 2013. “#AskAlexi Are my Red Bulls going to smack NYCFC 3-0 in the first Hudson River derby?” was posted on Twitter by Peter Brownell on May 24, 2013.
   
     
Wikipedia: Hudson River Derby
The Hudson River Derby, also known as the New York derby, is the name given to the soccer local derby between the two teams based in the New York metropolitan area, New York Red Bulls and New York City FC. First played in 2015, the rivalry between the two started almost as soon as the announcement was made of the formation of NYCFC in 2013.
     
Twitter 
Smalrus™
@smalrus
A New York Derby: Red Bulls v. Cosmos?  http://ow.ly/2Haz1 (via @cnn) #football
6:50 PM - 20 Sep 2010
   
Twitter
Fiona
@tinfoilpal
I want the New York Cosmos to actually become a team and play in the MLS. Then there’d be a New York derby with the Red Bulls!
9:29 AM - 30 Jul 2011
   
Business Insider
MLS Chief Don Garber Makes Progress On Plan That Will Kill The NY Red Bulls
Jim Edwards Oct. 16, 2012, 11:42 AM
(...)
Bottom line: The arrival of the Cosmos in Queens could weaken soccer in New York, not strengthen it, no matter how much Garber salivates at the idea of a big New York derby rivalry.
 
Twitter
Michael Heinz
@MGHeinz
Cosmos/Drinks in the Hudson River Derby RT @MLStoQueens RT if you’d like to see a Queens vs. @NewYorkRedBulls rivalry! http://bit.ly/VL5D3r
2:29 PM - 9 Jan 2013
   
Twitter
MLS to Queens
@MLStoQueens
9 Jan 2013
RT @dwyercd: @MLStoQueens @NewYorkRedBulls The Two Rivers Tussle? The Holland Tunnel Haymaker? The George Washington Beatdown? #MLS
 
Michael Heinz
@MGHeinz
Replying to @MLStoQueens
@MLStoQueens @dwyercd @NewYorkRedBulls “Hudson River Derby” has often been used by the Borough Boys and some Drinks supporters already
2:53 PM - 9 Jan 2013
       
Twitter
Knud G. Ferdinand
@kgferdy25
There’s only one NY soccer team to me, the Red Bulls. But seriously I can’t wait for the New York Derby to happen. #NYCFC
11:18 AM - 21 May 2013
 
Twitter
Peter Brownell
@PBNoRegard11
#AskAlexi Are my Red Bulls going to smack NYCFC 3-0 in the first Hudson River derby?
1:03 PM - 24 May 2013
     
MLS
Mike Petke once headbutted Jason Kreis, now they’re New York derby coaching foes | SIDELINE
December 11, 2013 4:30PM EST
Andy Edwards
MLSsoccer.com
The New York derby will be chock full of fun and interesting storylines by the time it kicks off in 2015.
 
Twitter
Michael Heinz
@MGHeinz
Man, the NY Derby/Hudson River Derby/Bridge & Tunnel Derby/Game No One’ll Shut The Hell Up About Already is really happening #NYCosmos #RBNY
9:18 PM - 28 May 2014
 
Twitter
Michael Heinz
@MGHeinz
NY Derby. Gotham Derby. Hudson River Derby. Bridge and Tunnel Derby. Empire Cup. I don’t know, pick one. #NYCvRBNY #NYCosmos #RBNY #usoc2014
8:10 PM - 14 Jun 2014
       
6 March 2015, The Guardian (London, UK), “MLS leaves strike talk behind just in time for big kick-off” by Nick Ames, Sport sec., pg. 5, col. 1:
Perhaps this is where the New York City FC come in. The first-ever New York derby will take place against the Red Bulls on 11 May and the newcomers will certainly be an easy target for those seeking to stir up enmity.
 
7 May 2015, Orlando (FL) Sentinel, pg. C2, col. 5:
MLS game of the week
NYCFC at New York Red Bulls,
7 p.m. Sunday, Fox Sports 1
For actual quality-of-soccer purposes, the best games during the weekend could be Orlando City and New England of the Galaxy at FC Dallas, but many will want to tune in to see the first New York derby play out.
 
8 May 2015, Philadelphia (PA) Inquirer, “This Week in Soccer,” pg. C6, col. 2:
New York City FC at New York Red Bulls
7 p.m. Sunday
(ESPN2, ESPN Desportes)
The highly anticipated first Hudson River Derby kicks off on the Jersey side at the Red Bull Arena in Edison.
   
The Guardian (London, UK)
New York City FC host the Red Bulls in a rivalry fuelled by increasing disdain
New York’s soccer derby is new, but their rivalry is growing – thanks in part to the feeling that NYC FC are upstarts encroaching on the Red Bulls’ territory
Sam Blum
Fri 20 May 2016 15.30 EDT Last modified on Mon 20 Feb 2017 06.40 EST
When fans of New York City’s two MLS clubs – New York City FC and the Red Bulls – congregate at Yankee Stadium on Saturday afternoon, there will be chanting, the hoisting of massive banners and a palpable air of disdain. What’s become known as the Hudson River Derby is a nascent rivalry fueled by vitriol and modest violence. It’s an enmity that’s seen supporters from both clubs hurl fists and insults as a means of proving which team best represents the five boroughs.