Farmer Isaiah Scammon left Hancock County, Maine, for the California Gold Rush in 1849, but fortune eluded him. He heard of free land in the Oregon Territory made available by the Donation Land Claim Act of 1850. In 1852, he traveled to the lands north of the Columbia River in Oregon Territory. Canoeing down the Chehalis River he found an attractive location for a farm at the mouth Wynoochee River. This was also at the head of tidewater where ships from Grays Harbor and the Pacific Ocean could sail without assistance. Under the Act, married couples could claim up to 640 acres of public land and gain title by residing there five years and improving the property.
Scammon moved Lorinda (also spelled Lorendah) and their three daughters onto the claim, which turned out to be a natural stopping place for those traveling between Chehalis Point on Grays Harbor and Grand Mound. Lorinda started operating a public house providing food and lodging, informally called Scammon�s Hotel and Scammon�s Landing. Isaiah worked as a blacksmith, planted fruit trees, and operated a ferry.
Five-foot-tall Lorinda was deeply religious and she named the claim first Mount Zion, then Montesano. Isaiah platted a town of that name. In 1860, the Scammon home became the seat of Chehalis (later Grays Harbor) County. In 1886, voters moved the county seat from the Scammon home to Montesano north of the river. The Scammon claim became South Montesano.