Carrying President Barack Obama on his way to a town hall event at Facebook headquarters in Palo Alto, Marine One landed on Stanford’s Sand Hill fields at about 1:30 p.m. today.

The president had arrived at San Francisco International Airport aboard Air Force One earlier today on a two-day West Coast tour to discuss deficit reduction and raise money for his re-election campaign.

Stanford officials did not publicly announce where Obama would arrive, and none were on hand at Sand Hill fields when he landed, said University spokeswoman Lisa Lapin. Security measures impacted traffic on California Avenue and Page Mill Road near campus.

High-profile helicopter landings are rare at Stanford: the school’s general use permit with Santa Clara County prohibits campus helicopter landings except for at Stanford Hospital & Clinics or when a head of state is involved, Lapin said. Obama is the first sitting head of state to visit Facebook.

Obama was last in the Bay Area in February, when he dined with Stanford President John Hennessy, Facebook CEO Mark Zuckerberg, several Stanford alumni and donors and other Silicon Valley leaders in Woodside.

On Wednesday night Obama will attend two fundraising events in San Francisco. Lapin, the Stanford spokeswoman, did not confirm if or when he would depart from Stanford later today.

Photos by Zack Hoberg

See full coverage of President Obama’s visit to Facebook here.