The service is taking place in the church on the campus of the Seventh-day Adventist liberal arts college in Angwin.
About eight miles away, on Deer Park Road, a roadside memorial with four crosses and flowers marks the location where Luke Nishikawa, 22, Boaz Tak, 20, Chong Shin, 20 and Simon Son, 19, died when their Honda struck a Toyota pickup broadside on Deer Park Road.
The service is being streamed live over the college's Web site.
College president Richard Osborn told crowd today that students at the school will forever remember where they were when they learned of the four deaths. Osborn said the college has received support and condolences from around the world.
The college will continue to offer grief counseling on campus through Friday, when the school will close for a Thanksgiving break.
Prayers were offered for the students' families and for the family of Sandalio Martinez, of Angwin, the driver of the Toyota pickup, who suffered serious injuries in the crash.
Many students are wearing green ribbons bearing the letter "N" and the number "4," representing Newton Hall, the dorm of the four students who perished.
"If you had ever hoped a community would act a certain way in a crisis, this is it -- they have responded exactly as you would hope and beyond," said Robert Kurtz, dean of Newton Hall.