Peconic County is a proposed new county in New York.

Peconic County would be formed out of the eastern part of what is now Suffolk County and would tentatively include the towns of East Hampton, Riverhead, Shelter Island, Southampton and Southold. Some residents feel this region differs from the rest of Suffolk County which is more urbanized and think they would be better represented as a separate political entity within the state.

Although the geography of the county, being long and narrow, creates a physical separation, the county was more unified in the past, being similar to New England in character. As the suburbs of New York City have expanded, taking in, first Nassau County, and then the western part of Suffolk County, the early atmosphere of farming and fishing has slowly disappeared from Long Island, being replaced by high density communities, industry, and commerce. As this trend continues, the nature of Suffolk County will ultimately change completely, negating any effort to save the early character.