The Taokas people lived in this coastal area before Han Chinese migration reached the northwestern corner of Taiwan. They farmed and hunted the land that now makes up Dajia District. Han settlers began arriving around 1669, during the late Ming dynasty, most of them originating from Fujian Province — particularly from Quanzhou. The migrants brought their religious traditions with them, including devotion to Mazu, the sea goddess who protects sailors and fishermen.

Under the Qing Dynasty and then under Japanese colonial administration, the area was known as Taikō. When Nationalist governance replaced colonial rule, the name reverted to Chinese: Dajia, meaning roughly "big armor" — a name that traces back to the indigenous Taokas language, though the characters assigned to it are Chinese. On 25 December 2010, Dajia was elevated from a township within Taichung County to a district within the new special municipality of Taichung.

The Dajia Mazu pilgrimage leaves in spring each year, the exact date determined by the lunar calendar. Mazu — goddess of the sea, protector of those who cross water — has been worshipped at the Jenn Lann Temple in Dajia for generations. The pilgrimage circuit takes her statue through Taichung City, Changhua County, Yunlin County, and Chiayi County before returning home, a route of roughly 340 kilometers covered entirely on foot by the most devoted participants.

The procession is not solemn. Traditional folk arts companies join it. Performance troupes of every kind — contemporary, historical, local, international — stage their acts along the route. Pilgrims form friendships with strangers walking beside them. Those who cannot walk the full route join for sections, driving ahead to wait at temple gates, offering incense and food to the goddess and the marchers. In 2010, more than 2,000 worshippers from about 40 Mazu temples in mainland China joined the pilgrimage, a sign of the cross-strait religious connections that the political border has never fully severed.

The pilgrimage is Dajia's most famous export, but not its only one. Giant Manufacturing — now one of the world's largest bicycle companies, a brand recognized by cyclists everywhere — was established in Dajia in 1972. The company has grown far beyond its hometown origins, with production and sales global, but it began here, in this coastal district, as part of the Taiwanese manufacturing surge that transformed the island's economy in the latter half of the twentieth century.

Dajia East Pottery is another local specialty. The district's traditional ceramics tradition produced earthenware with regional characteristics. Alongside the pottery, Dajia is known for Nǎiyóu sū bǐng — a buttery, flaky pastry in a thin round shape that functions as a local souvenir confection — and for taro products, including a purple jade dessert made from local taro. Straw hats and woven products round out the traditional craft economy.

Dajia sits at the northwestern corner of Taichung, bordered to the north by the Dajia River — one of the major rivers of central Taiwan — and facing the Taiwan Strait to the west. The climate is subtropical, averaging around 24 degrees Celsius through the year. The Jenn Lann Temple dominates the town's religious geography and draws visitors throughout the year, not only during pilgrimage season.

Other temples cluster nearby: Wenchang Temple, Kuo Xing Temple. Parks, including Chenggong Park and Zhongzheng Park, offer green space within the district. The Sword Well is among the historical curiosities that draw the history-minded visitor. Two Taiwan Railway stations serve the district — Dajia Station and Rinan Station — and the Taiwan High Speed Rail passes through the eastern edge of the district, though no stop is planned there. From downtown Taichung, Dajia is accessible by train in under an hour: close enough to visit easily, distinct enough to feel like somewhere else.