What is the cost of mailing a 1 oz. letter to Wales UK?

The cost of mailing a 1 oz. letter to Wales, UK, from the United States typically falls under international postage rates. As of October 2023, the price for a First-Class International letter is around $1.50. However, it's advisable to check with the United States Postal Service (USPS) or a local post office for the most accurate and up-to-date rates, as they can vary based on changes in postal regulations and services.