The game at Belfast's Windsor Park will be the first meeting between the USA and Northern Ireland since 1948.
The March window was expanded to allow European teams to play three games. But teams in five groups are committed to play their first three World Cup 2022 qualifiers. Group A had five teams, but they have committed to fill their open dates with friendlies against World Cup 2022 host Qatar. That leaves just four teams -- one from each of the other four groups -- free on each of the three dates to play friendlies.
U.S. Soccer would like to schedule a second game, but there are not a lot of options.
Kazakhstan is the only one of the 12 European teams to have not yet lined up a friendly game for its third date. But the former Soviet republic poses logistical challenges, especially at the beginning of the window.
Mexico and Costa Rica will play European teams on March 27 then face each other three days later at a European venue. One option would be to play Honduras in Europe. The Catrachos will already be in Europe, where they face Greece on March 28.
Teams in South America and Asia also have World Cup qualifying in March. In Africa, there are the final two dates of 2022 Africa Cup of Nations qualifying. Cameroon, the 2022 Africa Cup of Nations, has not yet announced plans for March.
European friendlies (March window)
3-24 Kosovo-Lithuania, Belarus-Honduras
3-27 Wales-Mexico, Bosnia-Costa Rica
3-28 No. Ireland-USA, Greece-Honduras
3-31 Switzerland-Estonia, Sweden-Finland
Kazakhstan not playing March 24-25.