Belknap was named for J. H. Belknap, who lived along the McKenzie River and was the son of R. S. Belknap, responsible for developing Belknap Springs. J. H. Belknap had an interest in the toll road constructed over McKenzie Pass during the early 1870s. The Belknap family came to the state of Oregon in 1847 with the Orem family, followed by G. Belknap and J. Belknap in 1848. The Belknap Springs in Lane County were found by R. S. Belknap in November of 1869 and developed them, and he became the postmaster for the Salt Springs post office, which was established in October of 1874. The name for the Salt Springs office changed to Belknaps Springs in June of 1875, then Belknap Springs in 1891.