I just sorted my AT elevation profile data by % grade and thought folks might be interested to know which places were the steepest. This is based on the most recent GPS track and mileage from the ATC, with elevations pulled from the USGS National Elevation Database at every 0.1 mile interval. Note: Some climbs make the list multiple times but only the steepest 0.1 mile segment is listed. If the 2nd steepest part of the climb would make the list I added an (x2).
Overall:
Southbound (since 8/10 of the overall list are northbound):
Rank AT Mile State Grade (%) Location 1 1852.5 NH 48.9 NOBO ascent of Webster Cliffs 2 2194.9 ME 45.6 NOBO ascent of Mt Katahdin (x2) 3 1883.0 NH 43.2 NOBO ascent from Carter Notch 4 1947.4 ME 43.0 NOBO ascent of Moody Mtn 5 (tie) 1871.2 NH 41.5 SOBO ascent of Mt Madison 5 (tie) 1878.1 NH 41.5 NOBO ascent of Wildcat Mtn (x2) 7 2001.1 ME 41.1 NOBO ascent of South Crocker Mtn 8 1833.1 NH 40.3 NOBO ascent of Mt Garfield 9 1949.6 ME 39.8 NOBO ascent from South Arm Rd 10 1476.9 CT 38.6 SOBO ascent to St. John's Ledges
South of NH (Since 9/10 of the overall list are in NH and ME):
Rank AT Mile State Grade (%) Location 1 1871.2 NH 41.5 SOBO ascent of Mt Madison (x2) 2 1476.9 CT 38.6 SOBO ascent to St. John's Ledges 3 (tie) 1885.1 NH 38.4 SOBO ascent from Zeta Pass (x2) 3 (tie) 1998.9 ME 38.4 SOBO ascent of Sugarloaf Mtn 5 1920.9 ME 37.9 SOBO ascent from Mahoosuc Notch 6 1882.0 NH 36.9 SOBO ascent from Carter Notch 7 (tie) 1219.6 PA 35.2 SOBO ascent from Port Clinton 7 (tie) 1805.7 NH 35.2 SOBO ascent of Mt Moosilauke 9 132.7 NC 35.0 SOBO ascent from the NOC 10 (tie) 1819.2 NH 34.1 SOBO ascent of North Kinsman Mtn 10 (tie) 1961.2 ME 34.1 SOBO ascent of Bemis Mtn
Rank AT Mile State Grade (%) Location 1 1476.9 CT 38.6 SOBO ascent to St. John's Ledges 2 99.6 NC 35.4 NOBO ascent of Albert Mtn 3 1219.6 PA 35.2 SOBO ascent from Port Clinton 4 132.7 NC 35.0 SOBO ascent from the NOC 5 1512.3 CT 33.9 SOBO ascent of Bear Mtn (x2) 6 1689.9 VT 33.1 NOBO ascent from Clarendon Gorge 7 78.6 NC 33.0 NOBO ascent from Bly Gap 8 1261.6 PA 32.4 NOBO ascent from Lehigh Gap 9 (tie) 152.0 NC 31.6 NOBO ascent from Sweetwater Gap 9 (tie) 1601.2 MA 31.6 NOBO ascent to the MA/VT state line
By State (since 7/14 states don't appear on any of the lists above):
State AT Mile Grade (%) Location GA 19.1 28.4 SOBO ascent of Ramrock Mtn NC 99.6 35.4 NOBO ascent of Albert Mtn NC/TN 184.8 31.4 NOBO ascent of Rocky Top TN 421.4 29.0 SOBO ascent from Laurel Falls VA/WV 798.2 29.2 SOBO ascent of Bluff Mtn MD 1064.5 26.3 SOBO ascent to High Rock PA 1219.6 35.2 SOBO ascent from Port Clinton NJ 1354.6 30.1 NOBO ascent of Pochuck Mtn NY 1387.4 30.3 SOBO ascent of Agony Grind CT 1476.9 38.6 SOBO ascent to St. John's Ledges MA 1601.2 31.6 NOBO ascent to the MA/VT state line VT 1689.9 33.1 NOBO ascent from Clarendon Gorge NH 1852.5 48.9 NOBO ascent of Webster Cliffs ME 2194.9 45.6 NOBO ascent of Mt Katahdin