Thorp ( THORP) is an unincorporated community and census-designated place in Kittitas County, Washington, United States. In 2020, the population was 232. The town of Thorp is 100 miles east of Seattle, 8 miles northwest of Ellensburg, and 17 miles southeast of Cle Elum. It is located at the narrow west end of the Kittitas Valley, where high elev…Thorp ( THORP) is an unincorporated community and census-designated place in Kittitas County, Washington, United States. In 2020, the population was 232. The town of Thorp is 100 miles east of Seattle, 8 miles northwest of Ellensburg, and 17 miles southeast of Cle Elum. It is located at the narrow west end of the Kittitas Valley, where high elevation forests of the Cascade Range give way to cattle ranches surrounded by farmlands noted for timothy hay, alfalfa, vegetables, and fruit production.