"The programme at Madison Square Garden was overwhelming. It was very special to interact with members of the diaspora. A big thank you," the prime minister said in a tweet.
He added that the Indian American community has earned immense respect through their "hardwork, actions and strong values".
"We are very proud of them," he said.
The prime minister said he "urged Indian-American community to support our efforts towards a clean Ganga, which would be a historic transformation for India".
"Series of initiatives announced for the Indian American community will deepen their bond with India and make travel a lot easier," Modi said in another tweet, and also shared a link to his speech.
The prime minister addressed a 20,000 strong Indian diaspora crowd at the Madison Square Garden in New York Sunday, where he promised to deliver on the electoral promises and also exhorted the Indian-American community to join in the development effort for India.