Map of Sarnia, Canada

Sarnia is a city in Ontario, Canada, with a population of about 72,125. It lies at 42.9787°N, 82.4041°W. Sarnia is about 599 km (372 mi) southwest of Ottawa, the capital. The nearest city on our map is Clinton Township, 61 km to the southwest.

Sarnia at a glance

Where is Sarnia?

• Located in the Northern and Western hemispheres.
• Daylight ranges from about 9 h 00 min on the shortest day to 15 h 22 min on the longest day (around 21 December and 21 June).

Cities near Sarnia

• Clinton Township — 61 km southwest, United States
• Shelby — 62 km southwest, United States
• Chatham — 65 km south
• Saint Clair Shores — 67 km southwest, United States
• Sterling Heights — 68 km southwest, United States
• Roseville — 69 km southwest, United States
• Rochester Hills — 70 km southwest, United States
• Warren — 74 km southwest, United States
• Troy — 74 km southwest, United States
• Royal Oak — 81 km southwest, United States

Largest cities in Ontario

• Toronto — 2,794,356
• Ottawa — 1,017,449
• Mississauga — 717,961
• Brampton — 656,480
• Hamilton — 569,353
• London — 422,324
• Etobicoke — 365,000
• Markham — 338,503
• Vaughan — 323,103
• Kitchener — 256,885

Largest cities in Canada

• Toronto — 2,794,356
• Montréal — 1,762,949
• Calgary — 1,306,784
• Ottawa — 1,017,449
• Edmonton — 1,010,899
• Winnipeg — 749,607
• Mississauga — 717,961
• Vancouver — 662,248
• Brampton — 656,480
• Hamilton — 569,353

Map of Canada and all its cities →

Sources: place names, coordinates, populations and time zones from GeoNames (CC BY 4.0, data retrieved October 2026). Population figures are the latest values recorded in GeoNames; depending on the country they refer to the city proper, a municipality or a wider urban area, so they can differ from census or metro-area figures. Map © OpenStreetMap contributors.