What’s the oldest free public library in North America?
This article provides a couple of options, depending on your exact definitions of "oldest," "free," "public," and "library." There is not a complete consensus. Note that the source for many of these is the library's own website, so ymmv.
The Library Company of Philadelphia, founded 1731: first subscription library (aka, membership dues), but did allow borrowing books for free.
The Darby Library, founded 1743: the oldest library in continuous service, but was a subscription library until the late 1800s.
The Redwood Library and Athenæum, founded 1746: oldest library building continuously in use; originally a subscription library.
The Library Company of Burlington, founded 1757: originally a subscription library, but was the first to construct a library building, in 1789.
The Franklin Public Library, founded 1790: originally a collection of books donated to a town by Ben Franklin and lent to citizens free of charge.
The Scoville Memorial Library, founded 1803: the first library to be open to the public free of charge.
The Peterborough Town Library, founded 1833: the oldest free tax-supported public library.
The Boston Public Library, founded 1844: first publicly supported free municipal library.
The Sturgiss Library: oldest building that currently houses a library, built 1644--however, the library itself is newer.