Dallesport is a census-designated place (CDP) in Klickitat County, Washington, United States. The population was 1,202 at the 2010 census.
Traditionally a site of the Wishram tribe (Called Echeloots by Lewis and Clark), who lived on the north bank of the Columbia about 10 miles in both directions from The Dalles, Oregon. Although the Wishrams were included in the Treaty of Yakima, they resisted removal to the Yakama Reservation. Indian burials from Memaloose Island in the Columbia were removed to the Wish-ham Cemetery near Dallesport prior to the filling of Lake Celilo. The loss of their traditional fishing grounds at Celilo Falls during the construction of The Dalles Dam in March 1957 dealt both a spiritual and an economic blow to the tribe.
Originally called Rockport or Rockland Flats, this was the site of the first Ferry crossing in the area, beginning in 1854. Rockland Flats was the original seat of Clickitat County (The name of the county was spelled with a 'C' until an official name change in 1869), and remained so until 1878. Riverboat traffic moved up and down the river, but could not pass the falls at the Dalles and Celilo Falls. Portage was originally via a 19-mile long wagon road circumventing the falls. The Oregon Portage Railroad allowed passage of goods and travelers by rail beginning in 1863, but shippers chafed at the monopoly. in 1905, Congress approved 8.5-mile canal with locks on the north shore to bypass the falls. The Dalles-Celilo Canal opened May 5, 1915. The canal incorporated 5 locks with a total 90-foot lift. The canal remained in use until it was flooded by the Dalles Dam in 1957.