The Province of Manitoba passed legislation and allowed the formation of the R.M. of St. Clements on July 7, 1883. It was proclaimed law on November 16, 1883, and deemed effective on December 22, 1883. The boundary of this new municipality comprised of all the portion of the County of Lisgar, from the Red River to the line between Ranges 8 and 9, East, on the east, in Townships 13 to 18, both inclusive, whole or fractional with those portions of the parishes of St. Peters, St. Andrews, and St. Clements, and the Native Reserve lying east of the Red River, and Townships 19 and 20, Ranges 7 and 8 East fractional, east of Lake Winnipeg. The "town" of East Selkirk was absorbed into the Municipality of St. Clements in 1904.

The first elections were held in early January 1884 with Robert Hay being elected Reeve, along with 6 councilors, 2 for each of three wards.

In 1894, ward boundaries were changed to 6 different wards. This form of organization continued until 1998, when it was changed to 2 wards with three councilors elected for each ward. The first female councilor elected was Dorothy Craigie, elected in Ward 6 during the 1978 elections. The St. Clements Municipality changed the title Reeve to Municipal Mayor in 2007. The current Municipal Mayor is Steve Strang, who has held the position since the 2003 municipal election.

The current population of St. Clements according to the last census in 2006 is 9,706 – up from 9,115 in 2001, 8,516 in 1996, and 7,870 in 1992.