We documented changes in overstory species composition and foliar cover during a 23-year sampling period, compared woody species on three small islands in Lake Winnipesaukee, New Hampshire, and determined changes in dominant plant species over time. Floristic surveys had begun on these islands in 1901, and provided valuable information about earlier vascular plant composition. Three Mile Island, Hawk's Nest Island, and Blueberry Island were first sampled quantitatively in 1978, again in 1991, and most recently in 2001. The data compiled here are for woody vascular plant species found in long-term monitoring plots on the islands owned and/or managed by the Appalachian Mountain Club. Pinus resinosa, P. strobus, and Tsuga canadensis were the three most dominant species on Hawk's Nest throughout the study period. On Blueberry Island, Acer rubrum, Betula populifolia, and T. canadensis were the three most dominant woody species when sampling began. However, by 2001 Ilex verticillata, Myrica gale, and Vaccinium corymbosum were the three most dominant species. On Three Mile Island, P. strobus and Quercus rubra were the two most dominant species in 1978, but by 2001 A. pensylvanicum and Hamamelis virginiana were the dominants. Overall species richness within the permanent plots increased on Three Mile and Blueberry Islands, while the total number of species remained relatively constant on Hawk's Nest Island.