SR 109 highlighted in red
|Defined by Streets and Highways Code § 409|
|Maintained by Caltrans|
|Length||1.870 mi (3.009 km)|
|South end||in East Palo Alto|
|North end||in Menlo Park|
State Route 109 (SR 109) is a short, unsigned state highway in the U.S. state of California. It forms part of University Avenue in San Mateo County between U.S. Route 101 in East Palo Alto and State Route 84 in Menlo Park just west of the Dumbarton Bridge. Although the route is unsigned, it may be noted on some online maps.
SR 109 begins at U.S. Route 101 in East Palo Alto. It continues north, paralleling the city border with Menlo Park before entering Menlo Park and crossing a railroad. SR 109 passes by salt evaporators before terminating at SR 84 just west of the Dumbarton Bridge.
In April 1958, I-109 was proposed as a name for the route that is now Interstate 280. This proposal was rejected by AASHTO. The California State Route 109 designation was first defined in 1963, running from Sunset Cliffs Boulevard to Interstate 5 in San Diego. In 1972, that route was deleted and was redefined in 1984 as a route in Palo Alto.
The segment in East Palo Alto between US 101 and Notre Dame Avenue remains in local control. Under Cal S&HC § 409 (b), the state will not take control over this section until Caltrans and the city determine that it is in an "acceptable state of repair".
Except where prefixed with a letter, postmiles were measured on the road as it was when the route was established, based on the alignment that existed at the time, and do not necessarily reflect current mileage. R reflects a realignment in the route since then, M indicates a second realignment, L refers an overlap due to a correction or change, and T indicates postmiles classified as temporary (for a full list of prefixes, see the list of postmile definitions). Segments that remain unconstructed or have been relinquished to local control may be omitted. The entire route is in San Mateo County.
|East Palo Alto||||University Ave||Continuation beyond US 101|
|East Palo Alto-Menlo Park line||1.10||Notre Dame Avenue||South end of state maintenance|
|Menlo Park||1.87||(Bayfront Expressway) - Dumbarton Bridge, Fremont||North end of SR 109|
|1.000 mi = 1.609 km; 1.000 km = 0.621 mi|