Massachusetts and New Hampshire share a border, so it is theoretically possible to be standing in both states at once on I-95, but we don't recommend it. You probably mean the southern border of MA, so you're really asking how many miles of I-95 exist in Massachusetts. According to the Wikipedia page for I-95, there are 91.95 of them.
The driving distance is approximately 14 miles.
307 miles
about 1700 miles
It is 94.72 miles according to MapQuest.
From NYC to NC border it saves about 50 miles but.... The speed limit in Del is 55 and enforced by local cops which are everywhere and there are a lot of traffic lights along the way so it will take you longer than I95. If Del built a highway connecting I95 to the CBBT it would be a great ride and boost the local economy but the locals want to keep the "charm" of the area, so avoid the CBBT
Exit numbers correspond to mileage. That's 123 miles.
Google Earth cites the shortest route as 348 miles (on I95) - with a journey time of 5 hours 45 minutes.
13.5 hours on I95,
Using Route 1 to Route 9 through Brewer to St Stephan and then St. John New Brunswick to The Nova Scotia Border and into Amherst is about 6.5 hours and the "shortest" route at about 295 miles or 472 kms. If you are more interested in time take the I95 north to Howland and then NB highway 2E to Fredericton NB and then to the NS border. This route has bigger Highways, better speeds but a longer distance at 306 miles or 490 kms, your time should be about 30 to 40 minutes faster at 5.5 to 5.75 hours. IF good highways are a must then take the I95 all the way to Houton/Woodstock and the number 2 to NS border, a long 334 miles or 535 kms and 5.75 to 6 hours
0 - no tolls on I95
15 miles via I95 South according to Google Maps
About 70 miles 1 hour and 20 minutes. I40 Cary to I95 Fayetteville