Sunnyside was originally known as Bay Bulls Arm and is located at the head of Bull Arm in southwestern Trinity Bay. This area was the site of a brief meeting between colonists from Cuper’s Cove (Cupids) and a small group of Beothuk on November 7, 1612, when the two groups exchanged gifts and shared a meal. Accounts of the 1612 meeting suggest that there was a considerable aboriginal presence in Bull Arm in the 1600s, and archaeological investigations have confirmed the early presence of Europeans and Beothuk on nearby Frenchman’s Island. In the 1850's the first attempt to land a transatlantic telegraph cable was made at Bay Bulls Arm, but the cable broke. A second cable was later landed at Heart’s Content.

In 1869, the town had a population of 28 and residents depended upon local sawmills and the fishery for survival. At the turn of the century there were a total of 241 people in Bay Bulls Arm.

In 1921 the population had reached 337 and the town name had officially been changed to Sunnyside. By the early 1990s most people had jobs at Come by Chance oil refinery and in service industries and only a few full-time fishermen remained in Centre Cove. Nearby Great Mosquito Cove was chosen as the site for construction of the Hibernia Oil Production platform in 1990.

Forest fires were often started, among other causes, by hot cinders from passing locomotives. From the 1930s to the mid-1960s, the Newfoundland Railway used Centre Hill as the site for a fire tower.

With an elevation of 1153 feet (384 meters), Centre Hill provided a panoramic view of the surrounding countryside and bays. The tower was equipped with a telescope and a telephone to report fires. The need for a fire tower ended when diesel engines replaced the coal fired locomotives. After years of neglect, the original tower eventually fell to ruin.

Thanks to the efforts of the local Lions Club, a replica of the original fire tower will be erected on top of Centre Hill minus, of course, the telephone.

Each year in the second week of August, the town of Sunnyside holds the Sunnyside Center Hill Soiree which includes a hike along this spectacular trail.