49 CFR § 372.239 - Definitions.
For the purposes of this part, the following terms are defined:
(a) Municipality means any city, town, village, or borough which has been created by special legislative act or which has been, otherwise, individually incorporated or chartered pursuant to general State laws, or which is recognized as such, under the Constitution or by the laws of the State in which located, and which has a local government. It does not include a town of the township or New England type.
(b) Contiguous municipalities means municipalities, as defined in paragraph (a) of this section, which have at some point a common municipal or corporate boundary.
The following state regulations pages link to this page.