Boistfort is an unincorporated community in the northwest United States, in Lewis County, Washington, about twenty miles southwest of Chehali…Boistfort is an unincorporated community in the northwest United States, in Lewis County, Washington, about twenty miles southwest of Chehalis. The original one-room school in Boistfort was established in 1853 and was the first school district in Lewis County and the Territory of Washington.