The eastern endpoint of US 66 was always at US 41. The original 1926 terminus was at Jackson Boulevard and Michigan Avenue, as Michigan Avenue was designated US 41 in 1926. However, when US 41 through most of Chicago was relocated to Lake Shore Drive in 1938, Route 66 was extended an additional two blocks east on Jackson Drive through Grant Park, past Buckingham Fountain, to end at Lake Shore Drive on the shore of Lake Michigan. This last two-block section on Jackson Drive is two way; consequently, when Jackson was designated a one-way street in 1955, westbound Route 66 made a one-block long jog northbound on Michigan Avenue before continuing west on Adams.