Sylmar is a moderately diverse neighborhood in the San Fernando Valley region of Los Angeles, California.Historically, known for its profusion of olive orchards, Sylmar can trace its past to the 18th century and the founding of the San Fernando Mission. In 1890, olive production was begun in a systematic manner.lthough Sylmar is only 20 miles (32 km) from the Pacific Ocean, the Valley can be considerably hotter than the Los Angeles Basin during the summer months and cooler during the winter months.