The home state advantage proved too much for the candidates challenging the front-runners for the US major-party presidential nominations.
New York Republicans sided decisively with one of their own in brash billionaire Donald Trump, who was born in the borough of Queens and started his personal empire in New York City.
Democrats chose former first lady and secretary of state Hillary Clinton, who made New York her home as she left the White House 15 years ago and represented the state in the US Senate for eight years.
The city recognized the winners by bathing the top of the Empire State Building first in red light for Trump, then in blue light for Clinton.
Trump won a convincing 60 per cent of the vote in a victory that does not secure the conservative party's nomination but adds to his formidable advantage in delegates to the Republican convention in July.
"We are leading by a lot and it is impossible to catch us," Trump said with characteristic bravado as he claimed victory. "We are really really rocking and we expect we are going to have an amazing number of weeks," the candidate told supporters.
He won over voters in New York the same way he's won other states - by appealing to people who are angry with Washington and who like that he is a businessman not a politician.
Even after New York, however, Trump remains about 400 short of the absolute majority of 1,237 delegates that would assure him of the nomination. The party outsider, who mostly associated with Democrats until a few years ago, is expected to struggle to expand his support in the likely event of a contested convention.
Trump needs to continue building momentum into the next round of primaries on April 26 in Pennsylvania, Maryland, Rhode Island, Delaware and Connecticut, and 10 more states culminating with collossal California on June 7.
For Clinton, the New York win was almost cathartic, even though she was heavily favoured.
"Today proved once again there's no place like home," a jubilant Clinton told supporters, with results showed her winning 58 per cent of the vote.
Rival Bernie Sanders, a Brooklyn native who has represented Vermont in Congress for decades, came into the New York vote having won eight of the last nine state in the left-leaning party's presidential race. The opening minutes of vote counting after polls closed suggested a tight contest, but within an hour of polls closing Clinton pulled away.
Her campaign might not have recovered from a loss. She announced her decision to run in New York City about a year ago, set up her campaign headquarters in Brooklyn and campaigned heavily throughout the state. A defeat also would have raised the spectre of the 2008 elections, when the upstart Barack Obama snatched the nomination away from her.
Sanders, who had made much of his New York roots, spoke with reporters after two rallies late Tuesday in Pennsylvania.
His voice cracking with fatigue after weeks of heavy campaigning in New York, he recalled his campaign's humble beginnings a year ago.
"We have come a long, long way," he said. "We have taken on the entire Democratic establishment."
A self-described democratic socialist, Sanders vowed to fight on: "We think we have a very strong grass-roots movement that is going to be knocking on a lot of doors and making a lot of phone calls."