Kahlotus is a city in Franklin County, Washington, United States. The population was 193 at the 2010 census.
The first organized settlement of Kahlotus was by German immigrants, imported by the railroads, in around 1880. Among these settlers were several locally recognized pioneer families, including Hans Harder, who first platted the town in 1902 under the name "Hardersburg". The town was later renamed Kahlotus. The meaning of the word "Kahlotus" is uncertain. It is believe by many that it is a Native American word meaning "Hole in the ground", but it may instead mean "stinking water" or "bad water" in reference to the highly alkaline water in the nearby lake. A third possibility is that the town was named for a Palouse tribal chief and signer of the Yakima Treaty of 1855. His name appeared with various spellings, including Kohlotus, Quillatose (by future governor Isaac Stevens), Qalatos, and Kahlatoose.
Harder's platting of the town coincided with the reinstatement of service on the Oregon & Washington Railroad & Navigation line between LaCrosse and Palouse Junction (now Connell), crossing the north end of town parallel to present-day Highway 260. Soon after, the Spokane, Portland & Seattle Railroad began construction on a second railroad on the south shore of nearby Kahlotus lake, including tunnels through the basalt cliffs near the southeast corner of town. Kahlotus was officially incorporated on May 31, 1907. The town boomed during construction of the railroad, local legend claims that nearly 20 saloons, a bank, newspaper, brothels, and other businesses appeared to serve the railt crews.