Kekkai Sensen's Intended Association: Evil Living Among Humans
Both the fictional town 'Salem's Lot and the real city of Salem, Massachusetts are associated with witchcraft and evil living among regular humans. This fits the ethos of Kekkai Sensen's 「ヘルサレムズ・ロット」, which is the mystically transmogrified version of New York City after a gateway between Earth and the Beyond opened, so that extra-dimensional creatures and humans dwell in the same paranormal melting pot.
Origin of the Phrase 'Salem's Lot
Jerusalem's Lot, Maine is a fictional town created by Stephen King which he has used as the setting for a number of his novels, novellas, and short stories. Within his worldbuilding, the town is nicknamed 'Salem's Lot (including the apostrophe) and the Lot.
The town called 'Salem's Lot first appeared in his 1975 novel 'Salem's Lot, but has reappeared as recently as in his 2014 novel Revival.
According to Wikipedia, the description of the fictional town is:
The town that would become Jerusalem's Lot was founded in 1710 by a preacher named James Boon, the leader of a cult of schismatic Puritans. The cult became notorious in the region for its open embrace of witchcraft and for its amoral sexual practices, including inbreeding. Jerusalem's Lot became an incorporated town in 1765, but was abandoned in 1789 after Boon and his followers mysteriously vanished [...]
When Jerusalem's Lot was incorporated in 1765, Maine was still part of the Massachusetts Bay Colony. The town got its name from a myth about one of the earliest residents, Charles Belknap Tanner, who raised pigs; one of these pigs was named Jerusalem. One day, Jerusalem escaped from her confines into a nearby forest, and became aggressive and wild. Tanner began warning young children who trespassed on his property to "Keep 'ee out o' Jerusalem's wood lot," lest the pig devour them. Eventually, the phrase "Jerusalem's Lot" was adopted as the town name.
[...] Jerusalem's Lot has been identified as a residence for great and mysterious evil, particularly vampires.
Other Derivative Uses
The fictional town is also mentioned in Alan Moore's 2002-2003 comic book series The New Traveller's Almanac, in the 2002 Eminem song Lose Yourself, and in the 1993 Nirvana song Serve the Servants.
Katakana and Pronunciation
Kekkai Sensen's 「ヘルサレムズ・ロット」 (Herusaremuzu Rotto) sounds similar to both the fictional town 'Salem's Lot (「セイラムズ・ロット」 [Seiramuzu Rotto]) and the Japanese word for "Jerusalem" (「エルサレム」 [Erusaremu]).
The Japanese title for the novel 'Salem's Lot is 『呪われた町』 (Norowareta Machi, meaning "cursed town"). In the Japanese translation, the name of the town is katakana-ized as 「セイラムズ・ロット」 (Seiramuzu Rotto), using the spelling of Salem, Massachusetts (「セイラム」= Seiramu), infamous for witch trials, not the Japanese spelling of Jerusalem (「エルサレム」= Erusaremu). The place name Salem (perhaps ironically) is a hellenized form of the Hebrew word for "peace" (שָׁלוֹם = shalom).
In Hebrew, the pronunciation for "Jerusalem" is Yerushalayim:
「ヘルサレムズ・ロット」 is not a reference to the city of Jerusalem, but rather to a fictional town known for housing monsters and named after a pig.