 marine city is a city in st. clair county in the u.s. state of michigan. located on the west bank of the st. clair river, it is one of the cities in the river district north of detroit and south of lake huron. the population was 4,248 at the 2010 census. the city features auto ferry service to sombra, ontario, canada across the river. ==geography== *according to the united states census bureau, 
CanadaaUnited_States_border_towns Cities_in_Michigan Cities_in_St._Clair_County,_Michigan Populated_places_on_the_Great_Lakes