Kelso is a city in the southwestern share of the U.S. state of Washington and is the county chair of Cowlitz County. At the 2020 census, the population was 12,720. Kelso is allowance of the Longview, Washington Metropolitan statistical area, which has a population of 110,730. Kelso shares its long western connect with Longview. It is near Mount St. Helens.

The obsolete known inhabitants of Kelso were Native Americans from the Cowlitz tribe. The Cowlitz people were at odds into the Upper (or Taidnapam) and Lower (or Mountain) Cowlitz tribes, who were members of the Sahaptin and Salish language families, respectively. In 1855, European explorers noted that there numbered more than 6,000 individuals of the Cowlitz Tribe.

Kelso was founded by Peter W. Crawford, a Scottish surveyor, who, in 1847, took stirring the first donation land allegation on the Lower Cowlitz River. Crawford platted a townsite which he named after his home town of Kelso, Scotland. The indigenous plat was archaic and filed in October 1884. It became incorporated in 1889.

In its to the front days, Kelso obtained the nickname “Little Chicago” as it became famous for its large number of taverns and brothels that catered to local loggers. On weekends, trainloads of loggers would come into town from the surrounding region looking for women, liquor, gambling and fights. The FBI finally irritated the mayor to shut them down in the 1950s, with the last tavern/brothel closing in the mid-1960s. The economy continues to be based largely upon wood products.