BARANGAY I is located at the heart of Vigan. It is where the Financial and Commercial Institutions are located. Heritage Village is one of the main attractions where tourists from other countries as well as other provinces are destined. The Barangay has the population of 1,136 inhabitants belonging to more than 200 households. A good number of inhabitants are most professionals and businessmen. The biggest natural resources of the barangay is the labor force which is highly educated and industrious. Eighty percent of the inhabitants are Ilocanos, the rest are Chinese, and some are Tagalogs, Visayans and a few Indian Nationals (Bombays). Ilocano is the primary dialect spoken. Barangay I has been the center of Tourism and Commerce of Vigan.

The History of Barangay I is linked with the History of Vigan. It became known as Barangay I during the incumbency of the late President Ferdinand E. Marcos through the Presidential decree 559 which divided the Poblacion into Barangay.

It is the main attraction in Barangay I, and it is what Vigan City is known for - a street lined with Spanish Era houses and cobble-stoned streets, which led to Vigan's inscription in the list of UNESCO World Heritage Sites. Tourists can buy souvenirs or even ride a calesa (horse-drawn buggy).

Established in the 16th century, Vigan is the best-preserved example of a planned Spanish colonial town in Asia. Its architecture reflects the coming together of cultural elements from elsewhere in the Philippines, from China and from Europe, resulting in a culture and townscape that have no parallel anywhere in East and South-East Asia.

It is also known as St. Paul Metropolitan Cathedral, it is the seat of the Archdiocese of Nueva Segovia. Burial place of the great Ilocano poet Leona Florentino. Vigan Cathedral faces Plaza Salcedo, and is an imposing creamy-white building built in the "earthquake baroque" style with thick buttresses to support it through earthquakes and typhoons. A separate belltower (or belfry) was built 15 meters away from the main building -- so that if one structure was destroyed in an earthquake, then the other might still remain standing. The belltower is about 25 meters high and it is surmounted by a large bronze weathercock that is said to symbolize St Peter.

The influence of Vigan's Chinese residents on the design of the cathedral may be seen in the two Fu Dogs (Chinese guardian lions) on the outer doors and in the octagonal shape of the belltower.

The first church was built on this site in 1574 (by Juan de Salcedo) and was damaged in the earthquakes of 1619 and 1627. A second was built here in 1641; and the present baroque-style church was built in the 1800s.

• Punong Barangay - Edgar Formoso
• 1st Brgy. Kagawad - Rocky Formoso
• 2nd Brgy. Kagawad - Eduardo Alonzo Jr.
• 3rd Brgy. Kagawad - Corazon Amorin
• 4th Brgy. Kagawad - Victor Paolo Nolasco
• 5th Brgy. Kagawad - Willy Arellano
• 6th Brgy. Kagawad - Jimmy Aquino
• 7th Brgy. Kagawad - Dennis Que
• SK Chairman - Kathleen Cassandra Formoso
• Brgy. Secretary - Zenaida Dulay
• Brgy. Treasurer - Sheena Salomon