MiraCosta College is a public California community college serving coastal North San Diego County. Go, Spartans! | With an average class size of about 30 to 45, MiraCosta students rave about their professors and the personal attention they receive. Both students and staff enjoy a friendly atmosphere, and the feeling that we are all here to help one another. MiraCosta's district is coastal North San Diego County; approximately 35 miles north of San Diego and 90 miles south of Los Angeles.