The town comprises the communities of Ambassador Beach, Barretville, Belcreft Beach, Colchester, Edgars, Essex Centre, Gesto, Harrow, Klie's Beach, Leslies Corner, Levergood Beach, Lypps Beach, Marshfield, McGregor, New Canaan, Oxley, Paquette Corners, Seymour Beach and Vereker.
The current Town of Essex was created on 1 April 1999 through the amalgamation of the former towns of Essex and Harrow, along with the former townships of Colchester North and Colchester South. Each community has a distinct history prior to amalgamation. Colchester South is notable for lying farther south than the northern border of California.
The Talbot Trail was heavily attributed with causing Essex to grow significantly in the last half of the 19th century. The community achieved town status in 1890.
On August 10, 1907, at the Essex Station, which is the train station located in the town of Essex, Ontario there was a large explosion that sent shock waves across the county and even into some parts of nearby Michigan. The explosion took place at roughly 9:50 am when a train cart containing 5,000 pounds (2,300 kg) of nitro-glycerine ignited causing a massive explosion to take place. This explosion had vast effects on the immediate area as well as the surrounding outskirts of town. The blast sent debris up to and over 600 yards (550 m) away and killed two people in the process, and injured many more. The result could have been much more severe as a train of vacationers from Brantford on their way to Detroit was scheduled to arrive in the station seconds before the explosion but was luckily running late; this delay saved the lives of many travellers. The boom of the explosion caused plaster to fall from the ceilings of buildings in Windsor and windows to rattle as far as Detroit. The explosion also caused over 250,000 dollars worth of property damage to the immediate area surrounding the blast zone. The reason for the explosion was leaking packaging of nitro-glycerine on one of the train carts in the station at the time that eventually dripped onto the track and when a spark was created the whole cart ignited into a giant explosion. The crater left by the explosion was 20 feet (6.1 m) across and 10 to 12 feet (3.0 to 3.7 m) deep in the centre. Families all around town found their yards and in some cases even their bedrooms littered with debris that was hurled from this earth trembling event. The results of this event were many. People began to flock to Essex from all over the county to see the devastation that was left behind, and due to the type of transportation available at the time these visitors often could not make the return trip in the same day. This posed a serious problem for the accommodations available in the town as they could not keep up with these visitors and rooms were booked solid and food sources were being used up quicker than they could be replenished. Another result of this would be the need to rebuild, the Essex Station was one building very heavily damaged along with many other properties in the surrounding area and the money needed to do so would not be easy to acquire. In an investigation to see who would be responsible for the explosion and subsequently the deaths of the two men, it was deemed that the nitro-glycerine was improperly cured; however, the railway was held responsible for the improper handling of the explosive cargo. The company would be fined 125,000 dollars for their irresponsible actions and this sum would go toward the expenses of rebuilding the areas of town that were affected. This process of rebuilding would take more than two years before all of the buildings would be completely rebuilt. The town of Essex would feel the lasting effects of this explosion for years to come.
Years later in 1980 the town would face the difficulty of another devastating explosion. This one would be the result of a natural gas meter being struck by a car setting this combustible material into flames. This explosion would reap considerable damage on the town, but no one died. This explosion would have smaller effects on the town of Essex, but it would remind people of the scare that their ancestors had experienced in the early part of the century. The Essex Station that was hit in the first explosion was rebuilt to its previous form and remains a recognizable landmark in the town today. It is often visited by tourist due to its rich and historical past. The town has even had the station put on display in one of its outdoor murals that are scattered all over town. This landmark is a symbol of the town's past.