The SR 209 designation then made a right turn onto Cañon Street, curved to the southeast, and went downhill to the bayside location of the old La Playa Trail.

[2] As it continued northeast through the Roseville and Loma Portal neighborhoods, SR 209 intersected both Harbor Boulevard and Nimitz Boulevard before passing along the northwestern edge of Naval Training Center San Diego (now closed and redeveloped as Liberty Station)[2] and providing access to Marine Corps Recruit Depot San Diego at Barnett Street.

[1] The Rosecrans Street portion of the highway followed the route of the historic La Playa Trail, the oldest European trail on the west coast,[3] which connected the Spanish settlements in Old Town and Mission San Diego de Alcala with the ship loading and unloading area at La Playa.

[5] By July, work was to begin on grading Rosecrans Street through what was known as the city of Roseville in preparation for construction of the Point Loma Electric Railway line.

[11] The termination of the Point Loma streetcar line was considered in 1923, but the San Diego Electric Railway decided to keep it running after residents opposed the idea of using buses instead.

[19] There were concerns about a $3 billion shortfall in funding during May 1966, which caused the San Diego Chamber of Commerce Highway Committee to recommend the completion of SR 109 as a project.

[21] The eight-lane freeway was projected to relieve traffic in the Frontier Street area coming from the San Diego Sports Arena.

[23] The entire project was completed in September, with the road scheduled to open in October;[24] just a few months before, the routing of SR 209 had been determined.

[29] Except where prefixed with a letter, postmiles were measured on the road as it was in 1964, based on the alignment that existed at the time, and do not necessarily reflect current mileage.