Of the 15 parliamentary seats, polling would be held in Outer Manipur in two phases on April 19 and April 26.
Notifications for the elections to the 60-member Arunachal Pradesh Assembly and 32-member Sikkim Assembly were also issued on Wednesday beginning the process of filing of nomination papers.
According to the schedule announced by Chief Election Commissioner (CEC) Rajiv Kumar, the last date for filing nomination papers for the Lok Sabha and the assemblies in Arunachal Pradesh and Sikkim is March 27 and scrutiny of candidatures would take place the next day.
The last date for withdrawal of nominations is March 30.
The counting of votes for the Arunachal Assembly polls would be done on June 2 and for the Lok Sabha on June 4.
Of the 15 Lok Sabha seats going to the polls on April 19, five are in Assam and there are two seats each in Arunachal Pradesh, Meghalaya, Manipur (one partly) and one each in Mizoram, Nagaland, Tripura and Sikkim.
In the second phase on April 26, voting will be held in another five seats in Assam, the other seat in Tripura, and in the remaining part of Outer Manipur.
Polling will be held in the remaining four seats in Assam in the third phase on May 7.
In the last parliamentary elections in 2019, the polling was held in the eight northeastern states in three phases.
Of the region's 25 Lok Sabha seats, seven are reserved for the tribals, and one for the Scheduled Castes.
Election officials said that large contingents of the Central Armed Police Force (CAPF) have already been deployed in the poll-bound districts.
Besides the CAPF, state security forces in large numbers were also performing election related duties and regularly patrolling sensitive, vulnerable, mixed-population and border areas as part of their confidence-building measures.
As all the eight northeastern states share International Borders, senior security officials said that special security measures have been taken along the 1,643-km-long border with Myanmar, the 1,880 km border with Bangladesh, the over 1,300 km border with China, the 516 km border with Bhutan, and the 98 km border with Nepal.
This has been done to foil any cross-border illegal activities, infiltration, and misadventure in the run-up to the elections.