Complex sentence: Boundary-Similkameen was the name of a provincial electoral district in the Canadian province of British Columbia spanning the Boundary Country, around the towns of Grand Forks and Rock Creek west including Oliver and Osoyoos to the Similkameen valley towns of Keremeos and Princeton.
Split into simpler sentences: Boundary-Similkameen was a provincial electoral district in the Canadian province of British Columbia. It spanned the Boundary Country, around the towns of Grand Forks and Rock Creek west including Oliver and Osoyoos to the Similkameen valley towns of Keremeos and Princeton.