Beware, the 100 mile limit just went bye bye ...
https://www.nytimes.com/2017/02/21/us/politics/dhs-immigration-trump.html?hp&action=click&pgtype=Homepage&clickSource=story-heading&module=first-column-region®ion=top-news&WT.nav=top-news&_r=1
The policy also calls for an expansion of expedited removals, allowing Border Patrol and
Immigration and Customs Enforcement agents to deport more people immediately. Under the Obama administration,
expedited removal was used only within 100 miles of the border for people who had been in the country no more than 14 days. Now it will include those who have been in the country for up to two years, and located anywhere in the nation.
It might just be prudent to carry your Enhanced Drivers License, Passport Card or the GOES Trusted Traveler Card if you are a citizen and additionally your Green Card if you are a a non-citizen legal resident.
If you are a non-resident alien, best to have your I-94 or I-94W handy together with your Passport.
It is also true that in the past implicit profiling has taken place, so take that into account before deciding what to carry or not.
Reasonable precautions may save you a lot of time and prevent the total ruin of your vacation or business trip.