A nickname originally given to the Elmira Civil War Prison Camp by its Confederate prisoners. Hellmira can still be used as a derogatory term for the city of Elmira itself.
Austin is known as "Spamtown" because it's the headquarters of Hormel Foods, the makers of Spam, the famous canned processed pork product.
Montana is known as the "Last Best Place" to locals. After the Unabomber, Ted Kaczynski, was captured in a remote cabin outside Lincoln, Montana, Montana became pretty popular in the media as a great hiding place. People were actually printing t-shirts with an outline of the state of Montana, a depiction of Ted Kaczynski's headshot with his unkempt hair, as well as the "Last Best Place" mantra with the word "hiding" scribbled in between 'best' and 'place.'
Found in old NYC neighborhoods, most famously and densely in Brooklyn, this is a term used for homes made from "brownstone," which is a brown sandstone. The Bedford-Stuyvesant neighborhood in Brooklyn has the most brownstones in NYC. Many people think of The Cosby Show's Huxtable family when they think of Brooklyn brownstones (as they lived in a traditional Brooklyn brownstone).
Savannah has earned this somewhat dubious designation, probably due to the popularity of local 'ghost tours' among tourists.