While Oregon has no sales tax, Washington ranks No. 4 nationally for the highest combined local-state sales tax at 8.83%, according to the Tax Foundation research group. Tennessee ranks No. 1 in the country with 9.43%, while Idaho ranks 36th at 6.02%, and Montana, like Oregon, has no sales tax. Are you curious where the highest total sales tax rate is found? It’s a city in Arizona. Learn which one, and find other tax facts in this article from The Oregonian.