Four British bachelors, led by David Batey, homesteaded the area in 1878, the time logjam obstructions were cleared downriver at the site of Mount Vernon. In 1884-85, Batey built a store and home for the arrival of Cook's family from Santa Barbara, where he had been mayor for two terms. Cook intended to name his town Bug due to mosquitos, but his wife protested along with a handful of local wives. Cook was already the namesake for a town — Cook's Ferry on the Thompson River in British Columbia to the north. This time he derived a name from Spanish. He knew "cedra" was the word for cedar, so he replaced two letters to make the name unique, winding up with "Sedro.
That old town of Sedro, by the Skagit River on the northern shore, proved susceptible to floods. In 1889, Northern Pacific Railroad developer Nelson Bennett began laying track from the town of Fairhaven, 25 miles northwest on Bellingham Bay, and real estate developer Norman R. Kelley platted a new town of Sedro on high ground a mile northwest of Cook's site. The Fairhaven & Southern Railroad arrived in Sedro on Christmas Eve 1889, in time for Bennett to receive a performance bonus from the towns at both ends, and a month after Washington became the 42nd state in the Union.
Within months, two more railroads crossed the F&S road bed a half mile north of new Sedro, forming a triangle where 11 trains eventually arrived daily. Railroad developer Philip A. Woolley moved his family from Elgin, Illinois, to Sedro in December 1889 and bought land around the triangle. He built the Skagit River Lumber & Shingle Mill next to where the railroads crossed and he started his namesake company town there that was based on sales of railroad ties to the three rail companies, including the Seattle & Northern (forerunner of the Great Northern Railroad) and the Northern Pacific railroads.
Meanwhile a fourth town rose nearby when the F&S laid rails on a "wye" that led northeast from Sedro about four a half miles to coal mines. Bennett bought the mines, along with Montana mining financier Charles X. Larrabee, and they soon sold their interests to James J. Hill, owner of the Great Northern. The resulting ore soon turned out to be more suitable for coking coal and a town began there named Cokedale. Cokedale faded in importance when the mine declined and the other towns all merged on Dec. 19, 1898, as Sedro-Woolley. You can read extensive articles about these occurrences and local and Skagit River history at the online Skagit River Journal of History & Folklore (http://www.skagitriverjournal.com/ ).
On May 15, 1922, a large circus elephant known as Tusko escaped from the Al G. Barnes Circus, which was making one of its stops in Sedro-Woolley, at that time. The elephant stomped his way through the little logging town and right into local history, demolishing fences, knocking over laundry lines and trees, telephone poles, and a Model T along the way.
After logging and coal-mining declined, the major employers and industries became the nearby Northern State Hospital (a mental-health facility) and Skagit Steel & Iron Works, which rose from the back room of a local hardware store in 1902 to became a major supplier of implements and parts for logging and railroad customers and which manufactured machines and parts for the war effort in World War II and artillery shells, starting in 1953. By 1990, that company was gone and the hospital was closed but new industry is developing north of town, including robotics. In 2006 a new housing development began between the town and the old hospital site, projected to add at least 5,000 to the town's population.
There were 3,205 households out of which 37.5% had children under the age of 18 living with them, 49.8% were married couples living together, 13.5% had a female householder with no husband present, and 32.1% were non-families. 25.9% of all households were made up of individuals and 12.6% had someone living alone who was 65 years of age or older. The average household size was 2.62 and the average family size was 3.14.
In the city the population was spread out with 28.8% under the age of 18, 9.2% from 18 to 24, 29.3% from 25 to 44, 18.4% from 45 to 64, and 14.3% who were 65 years of age or older. The median age was 33 years. For every 100 females there were 90.3 males. For every 100 females age 18 and over, there were 84.8 males.
The median income for a household in the city was $37,914, and the median income for a family was $40,918. Males had a median income of $35,215 versus $23,636 for females. The per capita income for the city was $16,517. About 10.7% of families and 11.3% of the population were below the poverty line, including 12.9% of those under age 18 and 16.1% of those age 65 or over.