The Department of Health and Human Services released information about the investigation into the cases, currently underway by the Gallatin City-County Health Department.
The health department says the five people with confirmed cases are adults and children who are residents of Gallatin County and exposed to the highly-contagious virus while traveling outside of Montana.
DPHHS said all five people are unvaccinated against measles or unsure of their vaccine status.
The five people are under quarantine at home.
Health authorities have determined there were points of exposure to the general public and are working to contact other people who may have been exposed.
Vaccination is the best defense against measles.
Measles is a highly-contagious airborne disease that starts with cold-like symptoms but is known for a tell-tale red rash that appears about two weeks after exposure and can spread all over the body. Measles is particularly dangerous for infants who cannot be vaccinated against the virus.
The MMR vaccine is widely available in Montana.
According to the Gallatin County Health Department
public sites with potential measles exposure include Interwest Tire in Belgrade, on April 14th and North Coast Electric in Bozeman on April 11th.
