State Route 26 (abbreviated SR 26) is part of Maine's system of numbered state highways. It is a major regional route running for 96.7 miles (155.6 km) from downtown Portland to the New Hampshire border near Upton, where it continues as New Hampshire Route 26. It is a multi-state route along with NH 26 and its short extension into Vermont. The multi-state highway was first designated in 1922 as part of the New England road marking system as NEI 26. When the system was supplanted by the United States Numbered Highways in 1926, it was redesignated as state highways retaining the original number.