# U.S. Route 20 in Massachusetts

U.S. Route 20 (US 20) runs its easternmost 153 miles (246 km) in the U.S. state of Massachusetts. The highway crosses the state border from New Lebanon, New York, into Hancock and runs eastward to Boston, where it ends at Route 2 in Kenmore Square. It spends the vast majority of its journey paralleling I-90 (Massachusetts Turnpike), which has largely superseded US 20 for through travel. Still, US 20 directly serves many towns and local business areas which the turnpike bypasses.
US 20 is currently the longest numbered highway in the entire country, at an estimated length of 3,365 miles (5,415 km) between Boston and Newport, Oregon.
Parts of US 20 between the Worcester and Boston areas are part of an alignment of the Boston Post Road, an early colonial highway designated in 1673 for carrying mail between New York City and Boston. US 20 is still locally known as the "Boston Post Road" in the towns of Northborough, Marlborough, Sudbury, Wayland, and Weston.

## Route description
### Berkshire, Hampshire, and Hampden counties

US 20 begins its eastward trek crossing the New York state border into Hancock and passing through the southern edge of the Pittsfield State Forest before entering Pittsfield and serving as the northern terminus of Route 41. The highway enters downtown and meets US 7, near the western terminus of Route 9. After its intersection with US 7, US 20 heads south, and the two routes form a concurrency into the town of Lenox. In Lenox, Route 7A splits off from the main road to serve the center of town, and US 20 splits from US 7 shortly thereafter to travel through the town of Lee to the southeast. The highway passes through Lee and has an interchange with I-90 (Massachusetts Turnpike) at exit 10 (formerly exit 2), south of town, near the eastern terminus of Route 102. Becoming the Jacob's Ladder Scenic Byway for the next 30 miles (48 km), US 20 returns to its eastward direction at this point and closely parallels the Mass Pike, having three non-interchange junctions with it before entering the town of Becket and meeting Route 8. Route 8 northbound forms a concurrency with US 20 to directly serve the town, while the Mass Pike passes south of Becket. Upon crossing through the town center, Route 8 splits from US 20, and it continues eastbound, passing into Hampden County and the town of Chester.
US 20 passes through the small town of Chester and clips the southern portion of Huntington in Hampshire County before reentering Hampden County and passing through the town of Russell. In Russell, US 20 serves as the eastern terminus of Route 23, passes under the Mass Pike, and continues into Westfield to finish off the scenic byway. In Westfield, US 20 crosses the US 202/Route 10 concurrency in the city's center and serves as the northern terminus of Route 187 just to the east. US 20 begins to enter urban landscape as it crosses into West Springfield, making its way through downtown, intersecting US 5, and crossing the Connecticut River into the city of Springfield. Immediately upon entering the city, US 20 interchanges with Interstate 91 (I-91) at exit 6 (formerly exit 8), where it leaves the surface street (which is picked up by Route 20A), to join I-291, which begins just to the south. US 20 is concurrent with most of I-291, about five miles (8.0 km). It splits off from the interstate via exit 5, where it meets the eastern end of Route 20A and resumes its surface alignment on Page Boulevard in Springfield, rejoining its original alignment in Springfield on Boston Road. US 20, as Boston Road, serves as the southern terminus of Route 21 and proceeds east into the town of Wilbraham, where it continues to parallel the Mass Pike. In Palmer, US 20 serves as the southern terminus of Route 181 and then intersects Route 32, which provides close access to the Mass Pike at exit 63 (formerly exit 8). US 20 and Route 32 share a short concurrency in downtown Palmer, before US 20 splits and continues east. Before leaving Palmer, Route 67 meets its southern terminus at US 20. Brimfield is the last town US 20 passes through in Hampden County; it enters from the west, crosses Route 19 in the center of town, and proceeds out of town to the east.

### Worcester and Middlesex counties

US 20 crosses into Worcester County and the town of Sturbridge, immediately serving as the southern terminus of Route 148. The route continues east where it serves as the western terminus of Route 131 before having an interchange with I-84 at exit 6 (formerly exit 3). I-84 is another quick route north to the Mass Pike, as it ends there less than a mile (1.6 km) away. Route 49, a short connector to Route 9 in Spencer, has its southern terminus at US 20 east of the I-84 interchange. US 20 enters the town of Charlton, passing through the village of Charlton City where it serves as the northern terminus of Route 169 and intersects with Route 31. Continuing east, US 20 enters the town of Auburn, where it briefly has a concurrency with Route 12. Route 12 provides direct access to the Mass Pike at exit 90 (formerly exit 10), while US 20 has an interchange with I-395, which ends at I-290 north of the Mass Pike interchange. US 20 continues to the northeast, entering Millbury after briefly crossing into southern Worcester, where it has an interchange with the Mass Pike at exit 94 (formerly exit 10A), as well as with Route 146 which at this point has a concurrency with Route 122A. The route reenters Worcester, crossing over Route 122 in a non-highway interchange. Leaving Worcester, US 20 enters the city of Shrewsbury, having another non-highway interchange with Route 140 south of downtown. The highway continues to the northeast, once again having a non-highway interchanging with Route 9. Heading almost due north at this point, US 20 crosses into Northborough and turns back eastward, serving as the western terminus of Route 135 in the town center. Two local roads, Church and Hudson streets, provide access to nearby I-290, which runs to the north. US 20 proceeds out of Northborough to the northeast, crossing into Marlborough and Middlesex County.
US 20 enters Marlborough and interchanges with I-495 (also referred to as the Outer Circumferential Highway and the Blue Star Memorial Highway) at exit 63 (formerly exit 24), effectively crossing into Boston's western suburbs. The route directly serves the center of town, intersecting with Route 85 in the process. It is in eastern Marlborough where US 20 begins to be famously referred to as Boston Post Road, and the road continues eastward into the town of Sudbury. Leaving Sudbury, US 20 intersects the Route 27/Route 126 concurrency in Wayland, and continues into Weston. US 20 does not intersect any major roads or numbered highways in Weston but does follow an approximately mile-long (1.6 km) bypass of the Boston Post Road (appropriately named Boston Post Road Bypass) between Highland and Wellesley streets, where US 20 rejoins the road and continues east into Waltham. The entire length of US 20 in Weston is designated as the Boston Post Road Historic District, since it retains much of its rural 18th-century character. Immediately upon crossing into Waltham, US 20 has an interchange with the concurrent I-95/Route 128 at exit 41 (formerly exit 26), marking the change from suburban landscape to the urban landscape of metro Boston. US 20 serves as the eastern terminus of Route 117 and passes through the center of Waltham and its downtown, serving as Main Street east of Route 117. In Waltham, US 20 also serves as the western terminus of Route 60, an urban route serving Boston's northern suburbs. The route continues into the city of Watertown serving as its Main Street to Watertown Square, where it has a major junction with Route 16, which passes west and north of Boston, through Cambridge and Medford. US 20 becomes North Beacon Street at this point and continues southeast as it crosses into the city of Boston over the North Beacon Street Bridge.

### Suffolk County

US 20 briefly continues as Leo F. Birmingham Parkway upon crossing into the Boston neighborhood of Brighton, immediately intersecting the western end of Soldiers Field Road Extension. The route then turns right and continues as North Beacon Street again, crossing under the Mass Pike with no interchange. US 20 continues toward downtown, passing through the Allston neighborhood of Boston. Upon crossing Cambridge Street, US 20 becomes known as Brighton Avenue for a short distance. US 20 soon reaches Commonwealth Avenue, serving as the eastern terminus for Route 30. At this point, US 20 passes through the Boston University campus. US 20 meets Route 2 at the southern end of the Boston University Bridge, crossing over the Mass Pike for the final time without an interchange. Route 2, via Mountfort Street, Park Drive, and Beacon Street, turns from south to east to meet US 20 at Kenmore Square. Upon meeting Route 2 again, US 20 meets its eastern terminus, with Route 2 taking Commonwealth Avenue its final stretch to the Boston Public Garden and Route 28, where Route 2 meets its own end.
US 20's official eastern terminus is in Kenmore Square at the intersection of Commonwealth Avenue, Beacon Street, and Brookline Avenue.

## Major intersections

| County | Location | mi | km | Exit | Destinations | Notes |
| Berkshire | Hancock | 0.000 | 0.000 | | US 20 west – New Lebanon | Continuation into New York |
| Berkshire | Pittsfield | 3.336 | 5.369 | | Route 41 south to I-90 Toll (Mass Pike) / Route 102 – Richmond, West Stockbridge | Northern terminus of Route 41 |
| Berkshire | Pittsfield | 7.431 | 11.959 | | Route 9 east – Dalton | Western terminus of Route 9 |
| Berkshire | Pittsfield | 7.596 | 12.225 | | US 7 north – Williamstown | Western end of US 7 concurrency |
| Berkshire | Lenox | 12.845 | 20.672 | | Route 7A south to Route 183 – Historic Lenox | Northern terminus of Route 7A; former routing of US 7 |
| Western end of limited-access section |||
| Berkshire | Lenox | 14.132 | 22.743 | | Housatonic Street – Lenox Center, Lenox Dale | At-grade intersection |
| Berkshire | Lenox | 14.694 | 23.648 | | Route 183 south (Walker Street) – Historic Lenox, Tanglewood, October Mountain, Lenox Dale | At-grade intersection; northern terminus of Route 183 |
| Berkshire | Lenox | 15.001 | 24.142 | | US 7 south – Stockbridge, Great Barrington | At-grade intersection; eastern end of US 7 concurrency |
| Eastern end of limited-access section |||
| Berkshire | Lee | 17.405 | 28.011 | Bridge over Housatonic River | Bridge over Housatonic River | Bridge over Housatonic River |
| Berkshire | Lee | 18.766– 18.836 | 30.201– 30.314 | | I-90 Toll / Mass Pike / Route 102 west – Springfield, Boston, West Stockbridge, Albany, NY | Exit 10 on I-90 / Mass Pike; eastern terminus of Route 102 |
| Berkshire | Becket | 25.719 | 41.391 | | Route 8 south – Otis, Winsted, CT | Western end of Route 8 concurrency |
| Berkshire | Becket | 30.895 | 49.721 | | Route 8 north – Becket, Dalton | Eastern end of Route 8 concurrency |
| Hampshire | Huntington | 41.831 | 67.320 | | Route 112 north to Route 66 – Huntington | Southern terminus of Route 112 |
| Hampden | Russell | 48.016 | 77.274 | | Route 23 west – Blandford, Otis | Eastern terminus of Route 23 |
| Hampden | Westfield | 53.752 | 86.505 | | US 202 north / Route 10 north – Holyoke | Western end of US 202/Route 10 concurrency |
| Hampden | Westfield | 54.004 | 86.911 | | US 202 south / Route 10 south – Southwick, New Haven, CT | Eastern end of US 202/Route 10 concurrency |
| Hampden | Westfield | 55.770 | 89.753 | | Route 187 south – Feeding Hills | Northern terminus of Route 187 |
| Hampden | West Springfield | 61.577 | 99.099 | | US 5 – Agawam, Holyoke, Northampton | Rotary interchange |
| Hampden | Connecticut River | 61.697 | 99.292 | Bridge | Bridge | Bridge |
| Hampden | Springfield | 62.739 | 100.969 | | I-91 / Route 20A east – Holyoke, Greenfield, Hartford, CT | Western terminus of Route 20A; exit 7B on I-91 |
| Hampden | Springfield | 63.135 | 101.606 | Western end of freeway section | Western end of freeway section | Western end of freeway section |
| Hampden | Springfield | 63.135 | 101.606 | 1 | I-91 – Holyoke, Greenfield, Hartford, CT I-291 begins | Westbound exit and eastbound entrance; signed as exits 1A (south) and 1B (north); western terminus of I-291 |
| Hampden | Springfield | 63.261 | 101.809 | 2A | Chestnut Street – Springfield | |
| Hampden | Springfield | 64.012 | 103.017 | 3 | Armory Street | |
| Hampden | Springfield | 65.082 | 104.739 | 4 | St. James Avenue – Chicopee Falls | |
| Hampden | Springfield | 66.559 | 107.116 | 5 | I-291 east / Route 20A west to I-90 / Mass Pike – Chicopee, East Springfield, Boston | Signed as exits 5A (east) and 5B (west) eastbound; I-90 not signed eastbound; eastern end of I-291 concurrency |
| Eastern end of freeway section |||
| Hampden | Springfield | 70.388 | 113.279 | | Route 21 north (Route 141 west) – Ludlow, Chicopee, Indian Orchard | Southern terminus of Route 21; eastern terminus of Route 141 |
| Hampden | Palmer | 78.782 | 126.787 | | Route 181 north – Belchertown | Southern terminus of Route 181 |
| Hampden | Palmer | 79.794 | 128.416 | | Route 32 north to I-90 Toll (Mass Pike) – Ware, Barre | Western end of Route 32 concurrency |
| Hampden | Palmer | 80.775 | 129.995 | | Route 32 south – Monson, Stafford Springs, CT | Eastern end of Route 32 concurrency |
| Hampden | Palmer | 82.461 | 132.708 | | Route 67 north – Warren, Brookfield | Southern terminus of Route 67 |
| Hampden | Brimfield | 87.867 | 141.408 | | Route 19 – Wales, Stafford, CT, Warren, West Brookfield | |
| Worcester | Sturbridge | 92.813 | 149.368 | | Route 148 north – Brookfield, North Brookfield | Southern terminus of Route 148 |
| Worcester | Sturbridge | 94.467 | 152.030 | | Route 131 east – Sturbridge, Southbridge | Western terminus of Route 131 |
| Worcester | Sturbridge | 94.831 | 152.616 | | I-84 to I-90 Toll / Mass Pike – Hartford, CT, Boston, Springfield | Exits 6A-B on I-84; I-84 east not signed; former I-86 |
| Worcester | Sturbridge | 96.795 | 155.776 | | Route 49 north to Route 9 – Spencer | Southern terminus of Route 49 |
| Worcester | Charlton | 99.991 | 160.920 | | Route 169 south – Southbridge, Putnam, CT | Northern terminus of Route 169 |
| Worcester | Charlton | 100.393 | 161.567 | | Route 31 – Dudley, Spencer, Paxton | |
| Worcester | Oxford | 105.826 | 170.310 | | Route 56 – Oxford, Webster, Leicester | |
| Worcester | Auburn | 106.731 | 171.767 | | Route 12 south – Webster | Western end of Route 12 concurrency |
| Worcester | Auburn | 107.413 | 172.864 | | Route 12 north to I-90 (Mass Pike) – Auburn, Boston, Worcester | Eastern end of Route 12 concurrency |
| Worcester | Auburn | 108.624 | 174.813 | | I-90 (Mass Pike) / I-290 east / I-395 south / Route 12 – Norwich, CT, Worcester | Exit 90 on I-90 / Mass Pike; exit 11 on I-395; Route 12 not signed |
| Worcester | Millbury | 112.510 | 181.067 | | I-90 / Mass Pike / Route 146 (Route 122A) – Worcester, Providence, RI, Boston, Springfield | Exit 94 on I-90 / Mass Pike; exit 18 on Route 146 |
| Worcester | Worcester | 115.252 | 185.480 | | Route 122 – Grafton, Providence, RI, Worcester, Barre, Uxbridge | Interchange |
| Worcester | Shrewsbury | 117.548 | 189.175 | | Route 140 – Grafton, Shrewsbury | Interchange |
| Worcester | Northborough | 120.697 | 194.243 | | Route 9 – Westboro, Boston, Shrewsbury, Worcester | Interchange |
| Worcester | Northborough | 123.895 | 199.390 | | Route 135 east – Westboro, Hopkinton | Western terminus of Route 135 |
| Middlesex | Marlborough | 127.683 | 205.486 | | I-495 – Cape Cod, Lowell | Exit 63 A-B on I-495 |
| Middlesex | Marlborough | 129.519 | 208.441 | | Route 85 – Southboro, Milford, Hudson, Bolton | |
| Middlesex | Wayland | 139.707 | 224.837 | | Route 27 / Route 126 (Cochituate Road) – Sudbury, Concord | |
| Middlesex | Waltham | 144.589 | 232.693 | | I-95 (Route 128) to I-90 (Mass Pike) – Providence, RI, Portsmouth, NH | Rotary interchange; exit 41 on I-95 |
| Middlesex | Waltham | 145.808 | 234.655 | | Route 117 west – Maynard, Leominster | Eastern terminus of Route 117 |
| Middlesex | Waltham | 147.073 | 236.691 | | Route 60 east – Belmont, Arlington | Western terminus of Route 60 |
| Middlesex | Watertown | 149.373 | 240.393 | | Route 16 – West Newton, Cambridge | |
| Charles River | Charles River | 150.683 | 242.501 | North Beacon Street Bridge | North Beacon Street Bridge | North Beacon Street Bridge |
| Suffolk | Boston | 152.654 | 245.673 | | Route 30 west (Commonwealth Avenue) – Newton, Framingham | Eastern terminus of Route 30 |
| Suffolk | Boston | 153.365 | 246.817 | | Route 2 west (Essex Street) – Cambridge, Arlington | |
| Suffolk | Boston | 154.11 | 248.02 | | Route 2 east (Beacon Street) – Downtown Boston | Eastern terminus of US 20 |
| 1.000 mi = 1.609 km; 1.000 km = 0.621 mi Concurrency terminus Tolled |||||||

## Suffixed routes

Route 20A is a state highway located entirely within Springfield. The route, an alternate route of US 20, parallels the section of US 20 concurrent with I-291. The western terminus is at the junction of US 20 and I-91 in downtown Springfield east of where US 20 crosses the Connecticut River on the North End Bridge. The eastern terminus is at the junction between US 20 and I-291 northeast of the heart of the city.
This alignment provides an alternate to I-291, which overlaps US 20 for much of its length, but was originally an alternate to old US 20, which ran down State Street and Boston Road. This route was therefore never part of US 20 but has served as an alternate to two separate routes.
Major intersections The entire route is in Springfield, Hampden County.
| mi | km | Destinations | Notes |
| 0.00 | 0.00 | I-91 north / US 20 west – West Springfield, Westfield, Greenfield | Western terminus; exit 7A on I-91 |
| 0.31 | 0.50 | Route 116 north (Main Street) | Southern terminus of Route 116 |
| 4.15 | 6.68 | I-291 / US 20 to I-90 / Mass Pike / I-91 – Indian Orchard | Eastern terminus; exit 5B on I-291 |
| 1.000 mi = 1.609 km; 1.000 km = 0.621 mi Incomplete access ||||