The history of the city of Valenzuela is rooted in the pre-colonial era, with its official founding dating back to 1623. Initially, the settlement was named Polo, derived from the Tagalog word `pulô`, meaning "island." This name was chosen for a reason: the territory was surrounded by rivers, making it resemble an island and facilitating the development of fishing and agriculture. During the early Spanish period, Polo was part of a larger town before becoming an important agricultural center in the province of Bulacan.
A key moment in the city's history was its renaming in honor of one of its most famous sons—Dr. Pío Valenzuela. He was a physician and one of the leaders of the Katipunan, the revolutionary movement that fought for Philippine independence from Spanish colonial rule in the late 19th century. In 1960, to commemorate the national hero, a portion of the town, and later the entire territory, was given his name, forever linking Valenzuela to the country's rich revolutionary history.
Geographical location has always played a vital role in Valenzuela's development. Its proximity to Manila and its position along key waterways, such as the Tullahan River, helped transform it from a quiet agricultural settlement into a bustling economic hub. Over time, the city became an integral part of Metro Manila, evolving into a major industrial and residential district while preserving the memory of its historical heritage.