Davis is the most populous city in Yolo County, California, United States. Located in the Sacramento Valley region of Northern California, the c…Davis is the most populous city in Yolo County, California, United States. Located in the Sacramento Valley region of Northern California, the city had a population of 66,850 in 2020, not including the on-campus population of the University of California, Davis, which was over 9,400 in 2016. As of 2023, there were 40,850 students enrolled at the university, and is known as the biking capital of America