The decision has been taken to stage Irish's home clash with Sarries at the Red Bull Arena - home of Major League Soccer team New York Red Bulls - on March 12 next year.
Irish to face Saracens in New York
The venue holds 25,000 fans and organisers are hopeful of a sell-out due to the Big Apple's large Irish population and the fact that the match takes place just five days before St Patrick's Day.
Rugby union is currently the fastest-growing team sport in the USA and Irish chief executive Bob Casey felt it was a chance they could not let go begging.
"This is an enormous opportunity for London Irish and a chance for our club to gain exposure in one of the biggest sporting cities in the world," he said.
"The New York region has a significant Irish community and is renowned for its annual St Patrick's Day Parade, so it's the perfect time for our club to venture into this market."