American Highway Code US Route 23 History
. U.S. Highway 23 extended to north-south U.S. highway stuck between Mackinaw City, Michigan and Jacksonville, Florida.
. It is a unique route (1926) which originally reached only so far south as Portsmouth, Ohio and has since been extended.
. The designation will be more intact than that of many other routes within the north-central and Mid-Atlantic States, at least meant for now.
. US 23 were extended into Florida along U.S. Route 1 in 1951. When the 20th Street Expressway was built around downtown Jacksonville, U.S. route 1 has been moved but U.S. 23 is still remaining.
. It has never changed its route in Florida, though at one time it was planned to broaden south, maybe to Fort Myers through US 17, SR 19, SR 33, US 98, US 17, and SR 31.