33 CFR §110.50a

An area on the east side of Mason Island bounded as follows: Beginning at the shore line on the easterly side of Mason Island at latitude 41°20′06″; thence due east about 600 feet to latitude 41°20′06″, longitude 71°57′37″; thence due south about 2,400 feet to latitude 41°19′42″, longitude 71°57′37″; thence due west about 1,000 feet to the shore line on the easterly side of Mason Island at latitude 41°19′42″; thence along the shore line to the point of beginning.