The Central Plains Region is an informal geographic region of the Canadian province of Manitoba located in the south central part of the Canadian province of Manitoba, directly west of Winnipeg. Its major urban centre is the City of Portage la Prairie. Together with the Pembina Valley Region to the south, the Central Plains Region composes the broadeā¦The Central Plains Region is an informal geographic region of the Canadian province of Manitoba located in the south central part of the Canadian province of Manitoba, directly west of Winnipeg. Its major urban centre is the City of Portage la Prairie. Together with the Pembina Valley Region to the south, the Central Plains Region composes the broader cultural region of Central Manitoba. Geographically, the region is considered to be a part of southern Manitoba, and is serviced by the Southern Regional Health Authority.