 In the 2011 Census , the City of Sarnia had a population of 72 @,@ 366 , an increase of 1 @.@ 3 % from the 2006 Census . With a land area of 164 @.@ 71 km2 ( 63 @.@ 59 sq mi ) , it had a population density of 439 @.@ 354 / km2 ( 1 @,@ 137 @.@ 92 / sq mi ) in 2011 . 
