Lambton County's northeastern border follows the Ausable River and Parkhill Creek north until it reaches Lake Huron at the beach community of Grand Bend.

The largest city in Lambton County is Sarnia,[4] which is located at the source of the St. Clair River at Lake Huron.

Along with Sarnia, the population centres in Lambton County are: Corunna, Petrolia, Grand Bend, Wyoming, Forest, and Watford.

The district of Hesse included British territories west of Long Point (practically all of western Ontario).

Established during World War II, Sarnia and the area along the St. Clair River is home to a major processing centre for oil from Alberta.

The community of Grand Bend and the Pinery Provincial Park are especially popular tourist destinations, attracting thousands of people each week throughout the summer to their long, uninterrupted beaches.

Over the last 20 years, soybeans, wheat, and grain corn have accounted for over 80% of total area crop production in Lambton.

Lambton EMS has ten ambulances and employs approximately 150 full- and part-time Primary Care Paramedics.