California health officials have recorded 113 cases of measles in the state since December.
The outbreak began at Disneyland and spread into the community. Almost two-thirds of the infections were from people who visited or worked at the theme park in Orange County or had contact with an infected person.
But the California Department of Public Health said Friday the three new infections do not have any connection to Disneyland.
Most of those stricken with measles were not vaccinated. The highly contagious illness has made a comeback in the U.S. in recent years, brought in from Americans who caught the virus abroad or from international visitors.
At least six other states, Mexico and Canada have identified measles cases tied to Disneyland.