In October/November in the pacific northwest you can buy them at asian markets (though they're pricy) or find them in dishes at many japanese restaurants.
"Thousands of truffle-producing trees were planted, and production reached peaks of hundreds of tonnes at the end of the 19th century. In 1890, 75,000 hectares (190,000 acres) of truffle-producing trees had been planted."
In October/November in the pacific northwest you can buy them at asian markets (though they're pricy) or find them in dishes at many japanese restaurants.