Trimark Physicians Group in Fort Dodge and UnitedHealthcare have entered into a network relationship, a move the health insurance company said expands its provider coverage to all 99 Iowa counties. The contract, effective May 1, gives more than 400,000 UnitedHealthcare employer-sponsored, individual, Medicare and hawk-i plan participants in the state access to Trimark’s services. Trimark is a physician-managed network of 74 doctors and mid-level providers designed to provide primary care and selected specialty services in Northwest and Central Iowa. It operates seven rural health centers and 19 regional specialty clinics throughout its 13-county service area. Statewide, UnitedHealthcare’s comprehensive provider network includes more than than 5,400 physicians and 130 hospitals.