Today in Washington State History From Settlers of North Oregon convene a convention at Cowlitz Landing to form a separate territory on August 29, 1851. Sand Point on Lake Washington is first surveyed on August 29, 1855, and opened for settlement. Denny Regrade (Seattle) contract for second phase is issued August 29, 1903. Voters approve Langley Port District, later to become Port of South Whidbey, on August 29, 1961. King County limits development in environmentally sensitive areas on August 29, 1990.