The Petaluma Marathon was the first marathon held west of the Mississippi. Established in 1935, the 26.2 mile event was organized by the Petaluma Spartans, and originally ran a course from the Petaluma High School track, down Bassett Street, over to Sixth street, to D street, down Lakeville highway to the Old Adobe turning west and returning to town.
A later version of the marathon started in downtown Petaluma, then out Western Avenue, to Spring Hill Road, then past the Two Rock Army Base (Petaluma-Tomales Road). From there the runners headed for Chileno Valley Road, then back to Petaluma, according to the Argus-Courier (Nov 16, 1968)
Healdburg runner Leland “Clipper” Smith won the first Petaluma Marathon in 1935 and was a top contender for Team USA in the cancelled 1940 Tokyo Olympics. Smith also qualified for tryouts for the 1936 Berlin Olympics. Source: Healdsburg Tribune, Enterprise and Scimitar, Volume LXXIV, Number 47, 2 May 1938