In 1749, the Masonian proprietors granted the town as "Monadnock No. 3" (or North Monadnock) to Matthew Thornton and 39 others. The 40 grantees came mostly from middle and eastern parts of New Hampshire; none of them became settlers in the township. The deed of grant, which dated November 3, 1749, was given by Col. Joseph Blanchard of Dunstable.
The French and Indian War thwarted permanent settlement until the 1760s, when Irishman Henry Strongman moved from Peterborough. Other early settlers arrived from Sherborn, Massachusetts. In 1771, Governor John Wentworth incorporated the town, naming it after Strongman's birthplace: Dublin, Ireland.
Like all towns in this area, the terrain features hills and valleys. Farmers found the soil hard and rocky, but with effort it yielded maize, oats, barley and potatoes, with some wheat and rye. Orchards were common. The first census, taken in 1790, reported 901 residents. By 1859, there were 1,088. In 1870, the small mill town of Harrisville voted to separate from Dublin, leaving the latter with only 455 residents during the 1880 census.