L.A. Department of Public Health officials said Thursday the additional cases are part of a group of travelers who were in Northern Italy.
The new patients have been quarantined, and health officials are monitoring anyone who came in close contact with those who have been infected.
Including a previous case, there are now a total of 11 cases across the county, including a contracted medical professional who conducted passenger screenings at Los Angeles International Airport.
RELATED: LAX medical screener tests positive for coronavirus
The L.A. County Board of Supervisors on Wednesday declared a state of emergency, saying the declaration would allow greater coordination among various levels of government and stressing that they were acting out of "an abundance of caution'' and not panic.
In addition, California's first coronavirus fatality - an elderly patient who apparently contracted the illness on a cruise - prompted Gov. Gavin Newsom Wednesday to declare a statewide emergency as six new cases, including a medical screener at Los Angeles International Airport, were confirmed.
RELATED: California Gov. Gavin Newsom declares statewide emergency after 1st novel coronavirus death
Newsom said the emergency proclamation is intended to help procure supplies and resources quickly. He announced the move Wednesday afternoon during a news conference, hours after the patient's death in Placer County was announced.
The measure made California the third U.S. state to declare a state of emergency, joining Washington and Florida, amid 11 deaths in the United States.
California currently has 53 confirmed cases of coronavirus. More than 93,000 cases of the illness have been confirmed globally.
News of the new L.A. County cases came shortly after Orange County health officials announced that two people tested positive for the novel coronavirus, though the diagnoses were described as "presumptive positive," pending final confirmation from the Centers for Disease Control and Prevention.
MORE: 2 coronavirus cases reported in Orange County - and health officials warn to expect more
County Health Officer Dr. Nichole Quick said the county recently improved its ability to perform COVID-19 testing and therefore "we expect to see more cases here in Orange County."
How to prepare, protect yourself from coronavirus
The impact of the coronavirus is being felt all across Southern California.
For in-depth coverage of the new coronavirus, go to www.abc7.com/coronavirus
DEVELOPING: This report will be updated.
