The Adirondack Forty-Sixers are an organization of hikers who have climbed all forty-six of the traditionally recognized High Peaks of the Adirondack Mountains. They are often referred to just as 46ers.
The first 46ers were brothers Robert and George Marshall, and their guide and family friend Herbert Clark. The Marshalls thought up the idea after spending much of their childhood in the region and examining the collection of Verplanck Colvin maps owned by their father, Louis Marshall. They devised criteria for the high peaks they would climb, choosing any summit that was more than 4,000 feet (1,219 m) above sea level in elevation with at least 300 feet (91.4 m) of vertical rise on all sides and separated from the next closest summit by 0.75 mile (1.2 km). They initially planned to climb only the summits above 4,000 feet (1,200 m), of which there were 42, and did so between 1918 and 1924.
They climbed the 4,000 ft (1,200 m) mountains later, on the suggestion of friends.
At the time that they undertook this goal, there were no trails up many of the peaks, making this a particularly formidable accomplishment. One of the peaks, Mount Marshall in the MacIntyre Range, has since been named in honor of Bob, and the brook (Herbert Brook) that is the most popular approach has been named after their guide Herbert Clark.
Some go further and re-climb all the peaks in winter. The winter 46 season is from December 21 to March 21. Winter 46ers are entitled upon completion of the winter 46 to wear the "Winter 46-R" rocker patch. This is a very difficult task due to the severity of winters in the Adirondacks. Some peaks, such as Gothics, can require some technical climbing skill when covered with snow and ice.
As of January 3rd 2011, there were 473 winter 46ers, or 7.08% of the total all-time membership.