A pleasant, bustling city spread over the V-shaped valley formed by the conjunction of Patit Creek, which courses through the northern section of town, and the Touchet River, which cuts through the southern section.

Early history of Dayton centered around the point where Pioneer Bridge now crosses the Touchet River. Here a Native American trail crossed the stream, and the grassy flats were a favorite camping ground for Native American bands. Here, too, Lewis and Clark rested on their return journey in May, 1806, and 30 years later Captain Benjamin de Bonneville also camped here. In 1855 H. M. Chase, the first settler, took up lands at the bend of the Touchet, and other settlers soon followed. Among these was Henry C. Rickey, who erected a hotel and, in 1862, started a stage line between Walla Walla and Lewiston by way of the Touchet Valley. Newcomers continued to arrive in increasing numbers, particularly after the Civil War, but little thought was given to the establishment of a town until 1871, when the town site was platted and filed. Five years later the town was incorporated under the name of Dayton.

The town flourished. Situated at the intersection of stage routes, it profited from the transient trade of hundreds of men stampeding to the various mining districts. Additional impetus came from the discovery that the upper benchlands, as well as the valleys, were eminently suited to growing wheat. In 1875, it became the seat of Columbia County.

By 1880 Dayton had a population of 6,300. Then the wave began to recede: a series of fires, the coming of rail lines and the end of stage routes, the deflation of mining booms all contributed to the recession. Only agriculture continued to increase in importance.

The Dayton of 1940 was the hub of a highly productive farming area; the major crops were wheat, barley, hay, apples, and peas. Cattle, infamous Wheatland Shorthorns, were raised for beef, and an average of 20,000 sheep were raised annually in the county. The industrial plants included a pea cannery, apple-packing plants, sawmills, a box factory, a creamery, and several grain warehouses.

Dayton Days, an annual three-day event, continues to be held and features horse racing, bucking contests, stunt riding, and steer bulldogging.