History of King's Highway 18B (Amherstburg):
The Amherstburg Highway 18B Business Route was created when a diversion was built to bypass two sharp curves along Highway 18 in Amherstburg in 1958-1959. This new diversion was essentially an extension of Apsley Street (now known as Sandwich Street) from Park Street southerly to the existing route of Highway 18 south of Amherstburg. Following the completion of the Amherstburg Diversion in 1959, the route of Highway 18 was relocated onto the new Apsley Street Extension. The old route of Highway 18 along the Detroit River was subsequently designated as Highway 18B. The Amherstburg Business Route was 2.2 km in length. Most of the route of Highway 18B was situated within the Town of Amherstburg, and was thus not assumed by the province. The section of Highway 18B within the Town Limits was entirely under municipal jurisdiction and was not formally designated as a Municipal Connecting Link. Only a small 1/2-mile section of Highway 18B lying south of the Amherstburg Town Limits was under provincial jurisdiction.
On June 1, 1970, jurisdiction over the provincially-owned section of Highway 18B was transferred to the Township of Malden. The route of Highway 18B was omitted from all provincial highway mileage logs dated 1970 and later, which suggests that the business route ceased to be signed around that time. The former route of Highway 18B through Amherstburg is now known as Dalhousie Street and Richmond Street.