Lumber and granite quarries were important in the early economy. The island is a self-sustaining environment that operates on an honor system; however, infrastructure such as electricity is provided by National Grid US. There are no bridges onto Grindstone (save when the river freezes), or formal ferry services onto Grindstone Island. There is a community dock (the town dock in Aunt Jane's Bay) provided for visitors on Aunt Jane's Bay - some inlanders who live inland on the island park their vehicles along the road. There is a normal US postal service delivery route onto the island Monday through Saturday.