Realmilk.com contains listings of raw milk vendors by state, while your local Weston A. Price Foundation chapter can also advise you on where to purchase certified raw milk. Some retailers may stock certified raw milk, depending on state regulations.
If retailers in your state are not allowed to sell raw milk, you may need to go to a farmer's market to buy directly from the farmer. Some areas have cow share and cow herd co-op programs that also offer raw milk to consumers.
A dairy may be Certified Raw, which means you can buy their milk with no concerns. Dairies that are not certified, however, may still adhere to Raw Milk Standards USA.