Our mission at Great Western Petroleum is to provide products and services to our customers at a competitive price, while add ... ing value through long term relationships, excellent customer service, and our broad knowledge of the petroleum industry. We supply branded and unbranded fuels along with lubricants to retail and wholesale businesses, agricultural, aviation, small business, commercial, and government consumers across Montana, Idaho, and Washington. In addition to supplying fuel, GW Petroleum owns and operates several convenience stores. read more