Close-up of a rusty cylinder on Fluke Street, the Isle of May. The Isle of May is located in the north of the outer Firth of Forth, approximately 8 km (5.0 miles) off the coast of mainland Scotland. It is about 1.5 kilometres (0.9 miles) long and 0.5 kilometres (0.3 miles) wide. The island is owned and managed by NatureScot as a national nature reserve.