Insular, provincial, parochial, local, small-town are comparable when they mean having or indicating the limited or restricted point of view considered characteristic of the geographically isolated.
Insular is usually applied to people or the ideas of people who are in one way or another isolated, so that they become or are regarded as self-contained or self-sufficient and disinterested in matters remote from their own concerns. The term implies an aloofness that proceeds from this isolation, but it usually also connotes narrowness of attitude, circumscription of interests, or prejudices in favor of one’s own people or one’s own kind (as of customs, literature, and art).
Provincial sometimes applies to what is characteristic of outlying districts as in opposition to what is characteristic of such metropolitan centers as London or New York.
Parochial, with its reference to a parish, a local unit of administration in the church or, in some regions, in the state, implies confinement to views and interests of a particular place and connotes extreme narrowness and, often, intolerance.
Local comes very close to parochial in meaning, but it carries a less distinct suggestion of narrowness or of intolerance; it rather implies the strong impress produced by the place in which one lives on one’s speech, one’s customs, or one’s interests and is distinguished from broad or general.
Small-town implies a relation to smaller towns as opposed to larger, or metropolitan, centers and thus comes close to provincial and local; distinctively, it often stresses the dullness or gaucheness or philistinism felt to characterize such an environment.