Region 3 comprises with the seven provinces in the central plain of Luzon namely; Aurora, Bataan, Bulacan, Pampanga, Nueva Ecija, Tarlac and Zambales. It has a total land area of 2,147,035 hectares. About 30 per cent of the total land area estimated at 644,475 hectares are devoted to agricultural production.
NIA Region 3 has nine (9) offices which was clustered to reduce in three(3) Irrigation Management Offices. The Provincial Offices of Bulacan, Aurora and Nueva Ecija was merged to create the BANE Irrigation Management Office; the Pampanga, Bataan, Pampanga Delta RIS and Colo Caulaman RIS comprised the PAMBAT Irrigation Management Office and the Tarlac, Camiling RIS, Zambales and Nayom Bayto RIS was merged to form the TARZAM Irrigation Management Office. And of course, the Regional Office which is located in Barangay Tambubong, San Rafael, Bulacan.
The entire NIA Region 3 was headed by Regional Manager Engineer Josephine B. Salazar while BANE IMO was headed by Engineer Lauro E. Ballesteros, the PAMBAT IMO by Engineer Isabelito V. Bitangcol and the TARZAM IMO by Engineer Jaime A. Mananghaya.