Dexter is an unincorporated community in Lane County, Oregon, United States. It is located near Dexter Reservoir, a.k.a. Dexter Lake, a reservoir of the Middle Fork Willamette River along Oregon Route 58. A post office was established in the locality in 1872 and named "Butte Disappointment", after a local landmark named in 1848. The post office was renamed "Dexter" in 1875, apparently after the "Dexter" brand cook stove owned by the postmaster's family. The Lost Valley Educational Center is an intentional community near Dexter.