And it's not close.
In fall 2017, 54.8 percent of Cal Poly's student body identified as white, which is the highest mark of any school within the 23-campus CSU system, as well as the 10-university UC system.
The next-closest schools in the CSU — home to 484,297 students — are the Maritime Academy (48.5 percent white), Sonoma State (44.6) and Chico State (43.0). (Fresno State was at 19.6 percent.)
Additionally, Cal Poly has the lowest percentage of African American students among all public universities in the state, the data shows.
Cal Poly's student body in fall 2017 was 0.7 percent African American — the ninth consecutive year under 1 percent — making it the only school in the state with an African American population less than 2 percent this academic year.
Cal State Dominguez Hills has the largest African American population at 12.3 percent, followed by Cal State East Bay (9.8), Sacramento State (5.8) and CSU Bakersfield (5.6). Fresno State is at 3.0 percent.
Cal Poly's racial divide has been under the microscope in recent weeks after multiple racist photos emerged on social media, prompting President Jeffrey Armstrong to place all fraternities and sororities on suspension.
Looking at the CSU system as a whole, Mexican American students make up the largest ethnic group at 31.8 percent, followed by white students (23.5 percent) and Asian students (11.6). That means Cal Poly's proportion of white students is more than double the CSU average.
On the UC side, Asian students comprise the largest ethnic group at 33.7 percent, followed by Latino students (24.2 percent) and white students (22.5).
None of the 10 UC schools has a white population larger than 34 percent, including universities comparable to Cal Poly such as UC Davis (24.7) and UC Santa Barbara (31.8).
"They're really unique in the system, in terms of both their geographic setting, the programmatic offerings and the way they're set up," said Mike Uhlenkamp, senior director of public affairs for the CSU. "So they pull not only from the state, but they pull from across the country, which is unique for CSU campuses, which lends to their demographics."
Still, Armstrong noted that Cal Poly has made progress in diversifying its campus over the last decade.
In 2005, more than 67 percent of Cal Poly students identified as white, and that number has been declining nearly every year since.
Cal Poly spokesman Matt Lazier said applications for under-represented minorities for fall 2018 were more than double the number the university received in 2008. He reiterated that Cal Poly is "committed to, and has a documented track record of, supporting diversity and inclusion."
"The effort is ongoing," Lazier said, "and the university's work is not complete until Cal Poly's faculty, staff and students reflect the diversity of the state of California in every facet — gender, race, sexual orientation, class, ideology, ethnicity and more."
According to Statistical Atlas, a website that analyzes data from the U.S. Census Bureau, California's ethnic break down as of July 2017 was 39.7 percent white, 37.4 percent Hispanic, 13.3 percent Asian, 6 percent African American, 2.6 percent mixed and 1.0 percent other.
San Luis Obispo County is more than 70 percent white and 20.9 percent Hispanic, according to Statistical Atlas.
Uhlenkamp said Cal Poly's distance from major cities, its polytechnic core and the highest students fees in the CSU system are all factors in the university's lack of diversity.
"In terms of the overall ethnic breakdown for CSU campuses — with the exception of Cal Poly because of their mission — the majority of our campuses really, in terms of the demographic look, is a reflection of the changes in ethnicity throughout California," Uhlenkamp said.