— The number of seats in the House of Commons is reviewed after each 10-year census. The number of seats can be changed in accord with the population growth.
— After the last census in 2011, 30 seats were added to the Commons, mainly to represent areas of high population growth.
— Ontario gained 15 seats, British Columbia and Alberta got six each and three went to Quebec.
— The boundaries of the new constituencies were drawn by 10 independent commissions, which also amended the maps of existing ridings.
— Only 44 of the 308 seats from the last election remain unchanged by the boundary commissions.
— As well as drawing electoral maps, the commissions also name the ridings. The names can be changed by a private member's bill in the Commons.
— The House of Commons began in 1867 with 181 seats. By 1952, there were 265 seats. The total hit 301 in 1999 and 308 in 2006.