From an article entitle The Great Road by Charles E Hatch, Jr.:
On May 13, 1607, the first permanent English settlers in the New World brought their three ships close to the shore at Jamestown Island, lying prominently in the James River, and began their settlement in Virginia. They established themselves in the western part of the island since here was much of the higher ground, particularly that bordering on the James, and consequently the most suitable part for settlement. It, also, was closer to the isthmus that then connected the island to the mainland, forming, as one contemporary author phrased it, a 'semi-island.'"