The Fram Group is a global automotive parts company with nine market-leading brands, and since 1932, it has been one of the largest manufacturers of oil filters in the United States. While not all FRAM oil filters are made in the US, most are. The company has seven lines of oil filters, including its iconic Extra Guard and FRAM Titanium oil filter. Baldwin purchased Hastings Premium Filters, and most of their oil filters are made in the US.
O'Reilly Auto Parts partners with Mann+Hummel, specifically Wix and Purolater, to produce its MicroGard brand of oil filters. Carquest, based in Raleigh, North Carolina, partners with Champion Laboratories to manufacture its automotive oil filters. Supertech oil filters are 100% made in the USA. Purolater continues to manufacture most of its oil filters in the United States, but since it is now part of a global filter conglomerate, you may see Purolater oil filters manufactured in different countries.
O'Reilly also works with Premium Guard and STP to make some of its MicroGard oil filters. Royal Purple, headquartered in Porter, Texas, partners with Champion Laboratories to manufacture its oil filters. Walmart used to partner with Wix but now produces its own line of oil filters through Champion Laboratories. It's worth noting that Champ Labs has a manufacturing facility in Shanghai, China, and some oil filters may be manufactured there. Fleetguard has manufacturing plants in Mexico and Australia, so you can expect some Fleetguard oil filters to be manufactured there as well.
STP, based in Boca Raton, FL, partners with Champion Laboratories to manufacture its oil filters. The Fram Group products made in China include the Fram Fresh Breeze Cabin Air Filter (CF10729), Fram Breeze Cabin Air Filter (CF10373), and Fram Oil Filter Cartridge (CH10246).