The chief minister was addressing a press conference at the BJP headquarters here after the party's good show in assembly polls in Tripura, Nagaland and Meghalaya.
"The BJP's sterling performance in northeast will go a long way in fulfilling development aspirations of people," he said.
Mr Adityanath said for the first time after Independence, these northeastern states will get chance to join the national mainstream and enjoy fruits of development.
The UP chief minister, who had campaigned for the saffron party in these assembly elections, said Prime Minister Narendra Modi's development oriented policies and organisational skills of BJP President Amit Shah led to his party's "sterling performance".
"That day is not far when one party will be in power right from Kashmir down to Kanyakumari," he said.
He also exuded confidence that the BJP will win Lok Sabha by-elections next week in Gorakhpur and Phulpur constituencies in Uttar Pradesh.
Continuing its winning streak, the BJP wrested Tripura, and received invitation to be part of the government in Nagaland, while Meghalaya elected a hung Assembly.
Get the latest election news, live updates and election schedule for Lok Sabha Elections 2019 on ndtv.com/elections. Like us on Facebook or follow us on Twitter and Instagram for updates from each of the 543 parliamentary seats for the 2019 Indian general elections.