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.