Opened on May 16, 2007, the mall is located on the east side of Epifanio de los Santos Avenue (C-4 segment) in Quezon City, giving significant market competition to the nearby SM North EDSA as one of the largest malls in Metro Manila.

The site of Trinoma used to be the location of "People's Park", a flea market built by former Mayor Brigido Simon Jr. as a livelihood project for the city's nearby informal settlers (the actual market's size, though, only covered what is now Trinoma's public transportation terminal and outdoor pay parking).

It was closed in 1995 by Mayor Ismael Mathay Jr. to give way for the construction of the Line 3 depot to service commuters along Epifanio de los Santos Avenue (EDSA).

When the Line 3 began operations in December 1999, the construction of the mall was not immediately undertaken due to lack of funding.

The North Triangle Depot Commercial Corporation was incorporated in 2001 with Fil-Estate spearheading the development and Ayala Land as minority stockholder.

[3] From December 1999 to December 2004, the depot was idle space[citation needed] until an agreement was signed between Ayala Land and the Fil-Estate Group with the former buying the latter's 30.89% stake in the North Triangle Depot Commercial Corporation for ₱600.1 million, and in exchange a land situated along Ayala Avenue, Makati and other shares.

Located on a 20-hectare (49-acre) parcel of land, Trinoma has a gross leasable area of 195,000 square meters (2,100,000 sq ft), which includes the mall's major anchor, The Landmark supermarket and department store.

It is directly connected to the North Avenue MRT station as the mall itself sits atop the Line 3 Depot.

These water features flow into pools at the Trinoma Park, a green area that sits atop the mall.