A number of hounds affirmed you can’t import pancetta into the United States. But JudiAU recommends online ordering from Niman Ranch or Salumi. They make quality products and, if you order from both, you can freeze what you don’t use right away.
pizzafreak says Bay Cities Italian Deli in Santa Monica and Domingo’s in Encino both sell a good pancetta. Claro’s Italian Markets (various locations) are another option.
notmartha recommends you drive to the Roma market in Pasadena, and adds: “Don’t get too put off by the strong cheese scent at the store, btw.”
Bay Cities Italian Deli [Westside–Beaches]
1517 Lincoln Boulevard, Santa Monica
Domingo’s Italian Grocery [San Fernando Valley–West]
17548 Ventura Boulevard, Encino
Claro’s Italian Markets [Various Locations]
Roma Italian Deli and Grocery [San Gabriel Valley]
918 N. Lake Avenue, Pasadena
Board Link: Desperate for Pancetta from Italy