S&S Petroleum, based in Mukilteo, Washington, started with one California gas station in 1998 and has expanded to 91 owned-and-operated convenience stores and fuel stations in Washington, Oregon, Idaho and California.

It does business as an ampm franchisee and operates unbranded stores and a Royal Mart in partnership with branded fuel marketers Mobil, Arco and Shell. S&S locations support a variety of community-based organizations, such as high school sports teams, the Boys and Girls Club of America, Toys for Tots, slain officer memorials, police fundraisers, children's hospitals and local food banks.

For benchmarking purposes, store counts are as of Jan. 1, 2023.

Headquarters:Mukilteo, Washington
No. of Stores:91
Rank Last Year:82