The 26-year-old Red Lodge-based athlete will be taking part in his first Games, and along with team-mates James Barnes-Miller and Ben Moore will become the first British athletes in history to compete in para-snowboard at the Paralympic Games.
Over 80 medals would be awarded across all sports.
The IPC had offered both countries the chance to march together under the same conditions as last month's Olympic Winter Games. But many South Koreans are unaware of the Games, and just days before the opening ceremony a poll showed only about a third of people knew when the Paralympics would begin.
The North Korean athletes - Kim Jong Hyon and Ma Yu Chol - may march with their counterparts from the South during Friday's opening ceremony for the Paralympics, which run until March 18.
South Korean ice hockey player Choi Kwang-hyouk was born in the North and lost a leg in a train accident as a child, before later defecting to the South. - AFP, March 8, 2018.
County under High Wind Advisory Monday
Temperatures should be held down by the cloud cover, but it will be windy again with gusts up to 30 miles per hour . The high winds are then expected to diminish Tuesday night when it is expected to be cool and clear.
Reclusive North Korea and the wealthy, democratic South are technically nonetheless at conflict as a result of their 1950-53 battle led to a truce, not a peace treaty.
Ten of the 13 medals have been gold as McKeever won two gold medals each in cross-country skiing at the 2002 Paralympic Winter Games in Salt Lake City and the 2006 Paralympic Winter Games in Torino, and three gold medals each in cross-country skiing at the 2010 Paralympic Winter Games in Vancouver and the 2014 Paralympic Winter Games in Sochi.
"Although we are disappointed, we respect the decision of the two NPCs who decided that marching separately would be better for both parties", IPC President Andrew Parsons said.
The Government of Canada is proud to see the Paralympic movement grow stronger and stronger, with athletes who continue to inspire all Canadians, especially our youth.
"In 2006... I can honestly say it's a moment I will never forget", Nicholson said.
Under a "false-flag" operation, Russian spies were found to be responsible for hacking the games of last year's Winter Olympics.
PyeongChang 2018 Organizing Committee President Lee Hee-beom said: "PyeongChang 2018 is ready to inspire, educate and excite the world".