1. Necanicum River: a 21-mile-long river that flows west off of Humbug Mountain alongside U.S. 26 only to change course as it nears the coast and head north, bisecting Seaside before depositing into the Pacific Ocean. The Necanicum River forms the first estuary south of the mouth of the Columbia River, providing many tributaries and wetlands with runoff as well as drinking water for the City of Seaside. Coho and other species of salmon utilize the Necanicum River for spawning
2. an unincorporated community located 13 miles east of Seaside in the foothills of the Coast Range alongside U.S. 26. Necanicum Junction has a convenience store and gas station and a bus stop served by both the Sunset Empire Transportation District and Amtrak
3. Necanicum Drive: a two-mile, north-south roadway in Seaside that hugs the west bank of the Necanicum River between First and 12th avenues.
4. Necanicum Watershed Council: servicing a population of less than 10, 000 over more than 54,000 acres and 86 stream miles that cover the Necanicum, Neawanna and Neacoxie water systems, the watershed council is responsible for providing municipal water to the City of Seaside and floodplain protection as well as protecting natural wildlife refuges and salmon breeding grounds
Most likely derived from the Tillamook Salish. Necanicum is thought to be an anglicization of Ne-hay-ne-hum, which was the name of an Indian lodge near the ocean and utilizes the prefix, ne-, meaning “place.” William Clark first marked it as Kil â mox (a variant that would eventually become Killamook, then Tillamook) to describe a “butifull river” that emptied into the Pacific, but later crossed it off his map and renamed it the Clatsop River on January 7, 1806, though that name would not stick. Known for awhile as Latty Creek, in honor of early pioneer resident William Latty, the river was recorded as Nekonikon in 1887. Necanacum and Nekanikum were other spelling variations. The community of Necanicum was first known as “Alhers” as the area post office was named after Herman Alhers, the first and only postmaster at the location. Alhers himself changed the name of the post office to “Push” in 1899, though the post office and town finally settled on Necanicum in 1907 due to the community’s proximity to the river. The post office closed in 1916, only one year after the U.S. Geological Board adopted the current spelling in 1915 based off a decision concerning local pronunciation. While it is accepted that the original meaning of the name is lost to history, Postmaster Alhers maintained that Necanicum meant “a gap in the mountains,” though many historians find this unlikely as the location of the original Indian lodge was close to the ocean.
“Mr. Grimes, Proprietor of the hotel which bears his name on Clatsop Beach, is engaged in the construction of a new bridge across Necanacum (or Latta’s), river which will very materially shorten the distance in that vicinity, and give a better road to travel.”
— “New Bridge,” Tri-Weekly Astorian, Thursday, July 3, 1873, P. 2
“Another important improvement planned for this year is the further improvement of the Twelfth avenue route to the beach. A bridge has already been constructed Necanicum river at this point, and by the improvement of the road to the beach and the laying out of a turnaround here facilities for reaching the ocean by automobile will be greatly increased and congestion relieved from the Broadway turnaround.”
— H. W. Lyman, “Seaside Prepares for Greatest Season,” The Sunday Oregonian, May 21, 1922, Section 6, P. 1