The New York State Thruway Berkshire Spur connects the Thruway mainline to the Massachusetts Turnpike. The spur is mostly part of I-90, but the westernmost miles do not have a signed route number. This portion includes the Castleton-on-Hudson Bridge.
| Mile | Eastbound | Westbound | Notes |
|---|---|---|---|
| Albany County | |||
| Speed Limit 65 | |||
| B0.0 |  |
Exits 21B-1 SouthNew York City |
|
| B0.0 | Exits 22-61 North To  Albany Buffalo |
||
| Rensselaer County | Albany County | ||
 |
 |
||
| B6.6 | Exit B1  Albany Hudson |
||
| Columbia County | Rensselaer County | ||
| B15.1 | Exit B2  Taconic State Parkway Passenger cars only |
||
| Virtual Ticket System Toll | |||
| B23.3 | Exit B3 Austerlitz New Lebanon Last exit before toll |
||
 |
 |
||
| Speed Limit 65 | |||
| B24.3 | Massachusetts Berkshire County |
New York Columbia County |
|