86 (MBTA bus)

86
A route 86 bus on Chestnut Hill Avenue in March 2022
Overview
System	MBTA bus
Garage	Somerville Garage[1]
Route
Locale	Boston, Cambridge, and Somerville, Massachusetts
Start	Sullivan Square station
End	Reservoir station (Cleveland Circle)
Length	6.79 miles (10.93 km) eastbound 6.70 miles (10.78 km) westbound
Daily ridership	6,150 (2018)[2]

Route 86 is a local bus route in Boston, Cambridge, and Somerville, Massachusetts, operated by the Massachusetts Bay Transportation Authority (MBTA) as part of MBTA bus service. It operates on a circumferential route between Sullivan Square station and Reservoir station (Cleveland Circle) via Union Square, Somerville, Harvard Square, and Brighton Center. In 2018, it had the 18th-highest weekday ridership on the system, though it ranked 37th by number of weekday trips.^[2] A 2018–19 MBTA review of its bus system found that route 86 had infrequent and unreliable service, including irregular scheduled headways, despite its high ridership and significance as a crosstown connecting route.

Transit service on three portions of the modern route date back to horsecar lines opened in the 19th century, with the section between Union Square and Sullivan Square opened in 1858. Two of those sections were converted to electric streetcars in the 1890s. Three overlapping bus routes (later designated 63, 86, and 91) were established between 1925 and 1931, replacing circumferential streetcar services and creating new connections. Route 86 ran between Union Square, Allston and Union Square, Somerville until it was extended to Sullivan Square in 1977 and 1981 to supplement route 91. In 1989, the western end was extended to Cleveland Circle, replacing route 63.

In December 2024, the eastern half of the route is planned to become part of route 109, with route 86 running only between Reservoir and Harvard.