The blue area is New York State; the red area is area code 585.
Area code 585 is a state of New Yorktelephonearea code. It was created on November 15, 2001, to serve the Rochester area. Before this, Rochester used to share the 716 area code with Buffalo. By splitting off the Area code 716, it is now reduced to just Buffalo and far western New York. Aside from new area codes created in the New York City metropolitan area and Long Island, 585 was the second new area code in New York since 1954, having been preceded by 845.
The border of 585 area code roughly matches county lines (without regard to mailing address) which causes confusion where a ZIP code overlaps a municipal boundary. Therefore, some ZIP codes have phone numbers in two area codes. Among these places: Arcade, Cuba, Akron, and Alden. A significant part of Ontario County uses 315. Part of the town of Farmington is north of the NY Thruway (Interstate 90), and is "joined" with Wayne County in the 315 area code.