Appendix B
Ecological Subregions of the United States

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Appendix B

Approximate areas and proportionate extent of subregions at the Province and Section level in the United States (Area is given in square miles rounded to nearest 100, and percentage to nearest tenth.)

                                                               Extent   Extent
                                                                 in       in  
Province  Section                                     Area    Province   U.S.
\hrule
                                                       mi2        %        %  

124\lf    124A-Coastal Plain\lf                       19,100               0.5

125\lf    \lf                                         46,900               1.3
          125A-Kotzebue Sound Lowlands\lf             12,100      25.8     0.3
          125B-Yukon-Kuskokwim Delta\lf               34,800      74.2     1.0

126\lf    126A-Bristol Bay Lowlands\lf                23,600               0.7

M121\lf   \lf                                        101,600               2.8
          M121A-Foothills\lf                          47,200      46.5     1.3
          M121B-Mountains\lf                          54,400      53.5     1.5

M125\lf   M125A-Seward Mountains\lf                   20,600               0.6
                                                                                
M126\lf   M126A-Ahklun Mountains\lf                   16,700               0.5

M127\lf   \lf                                         22,200               0.6
          M127A-Alaska Peninsula\lf                   14,600      65.7     0.4
          M127B-Aleutian Islands\lf                    4,500      20.3     0.1
          M127C-West Kodiak Island\lf                  3,100      14.0     0.1

131\lf    \lf                                         56,100               1.6
          131A-Upper Kobuk Valley\lf                  16,900      30.1     0.5
          131B-Yukon-Kuskokwim Bottomlands\lf         39,200      69.9     1.1

135\lf    \lf                                         15,700               0.5
          135A-Cook Inlet Lowlands\lf                  9,600      61.1     0.3
          135B-Copper River Basin\lf                   6,100      38.9     0.2

139\lf    139A-Upper Yukon Flats\lf                   13,000               0.4

M131\lf   \lf                                         55,000               1.5
          M131A-Nulato Hills\lf                       19,600      35.6     0.5
          M131B-Kuskokwim Mountains\lf                26,200      47.7     0.7
          M131C-Nushagak-Lime Hills\lf                 9,200      16.7     0.3

M135\lf   \lf                                         61,000               1.7
          M135A-Alaska Mountains\lf                   48,100      78.9     1.3
          M135B-Wrangell Mountains\lf                 12,900      21.1     0.4

M139\lf   M139A-Upper Yukon Highlands\lf              68,400               1.9
\hrule
                                                               Extent   Extent
                                                                 in       in  
Province  Section                                     Area    Province   U.S.
\hrule
                                                       mi2        %        %  

212\lf    \lf                                        147,300               4.1
          212A-Aroostook Hills and Lowlands\lf         3,800       2.6     0.1
          212B-Maine and New Brunswick Foothills and                   
                 Eastern Lowlands\lf                   6,700       4.6     0.2
          212C-Fundy Coastal and Interior\lf           2,400       1.6     0.1
          212D-Central Maine Coastal and Interior\lf   4,600       3.1     0.1
          212E-St. Lawrence and Champlain Valley\lf    4,600       3.1     0.1
          212F-Northern Glaciated Allegheny Plateau\lf         21,300      14.5     0.6
          212G-Northern Unglaciated Allegheny Plateau\lf        5,900       4.0     0.2
          212H-Northern Great Lakes\lf                31,100      21.1     0.9
          212J-Southern Superior Uplands\lf           30,300      20.6     0.8
          212K-Western Superior\lf                     8,200       5.6     0.2
          212L-Northern Superior Uplands\lf            7,400       5.0     0.2
          212M-Northern Minnesota and Ontario\lf       9,200       6.2     0.3
          212N-Northern Minnesota Draft and Lake Plains\lf     11,800       8.0     0.3

M212\lf   \lf                                         43,600               1.2
          M212A-White Mountains\lf                    17,600      40.4     0.4
          M212B-New England Piedmont\lf                6,100      14.0     0.2
          M212C-Green, Taconic, Berkshire Mountains\lf          7,100      16.3     0.2
          M212D-Adirondack Highlands\lf               10,300      23.6     0.3
          M212E-Catskill Mountains\lf                  2,500       5.7     0.1

221\lf    \lf                                        104,500               2.9
          221A-Lower New England\lf                   19,500      18.7     0.5
          221B-Hudson Valley\lf                        5,800       5.5     0.1
          221C-Upper Atlantic Coastal Plain\lf         5,300       5.1     0.1
          221D-Northern Appalachian Piedmont\lf        8,000       7.7     0.2
          221E-Southern Unglaciated Allegheny Plateau\lf       31,500      30.1     0.9
          221F-Western Glaciated Allegheny Plateau\lf          11,800      11.3     0.3
          221H-Northern Cumberland Plateau\lf         13,800      13.2     0.4
          221I-Southern Cumberland Mountains\lf        3,800       3.6     0.1
          221J-Central Ridge and Valley\lf             5,000       4.8     0.1

222\lf    \lf                                        270,000               7.5
          222A-Ozark Highlands\lf                     45,800      17.0     1.3
          222C-Upper Gulf Coastal Plain\lf            10,600       3.9     0.3
          222D-Interior Low Plateau, Shawnee Hills\lf          14,100       5.2     0.4
          222E-Interior Low Plateau, Highland Rim\lf  29,400      10.9     0.8
          222F-Interior Low Plateau, Bluegrass\lf     15,500       5.7     0.4
          222G-Central Till Plains, Oak-Hickory\lf    16,000       5.9     0.4
          222H-Central Till Plains, Beech-Maple\lf    27,100      10.0     0.8
          222I-Erie and Ontario Lake Plain\lf         18,800       7.0     0.5
          222J-South Central Great Lakes\lf           25,300       9.4     0.7
          222K-Southwestern Great Lakes Morainal\lf   18,000       6.7     0.5
          222L-North-Central U.S. Driftless and Escarpment\lf  16,600       6.1     0.5
          222M-Minnesota and Northeastern Iowa Morainal\lf     29,400      10.9     0.8
          222N-Lake Agassiz, Aspen Parklands\lf        3,400       1.3     0.1
\hrule
                                                               Extent   Extent
                                                                 in       in  
Province  Section                                     Area    Province   U.S.
\hrule
                                                       mi2        %        %  

M221\lf   \lf                                         68,100               1.9
          M221A-Northern Ridge and Valley\lf          32,100      47.1     0.9
          M221B-Allegheny Mountains\lf                 9,500      14.0     0.3
          M221C-Northern Cumberland Mountains\lf       5,500       8.1     0.1
          M221D-Blue Ridge Mountains\lf               21,000      30.8     0.6

M222\lf   M222A-Boston Mountains\lf                    6,400               0.2

231\lf    \lf                                        193,000               5.4
          231A-Southern Appalachian Piedmont\lf       73,200      37.9     2.0
          231B-Coastal Plains, Middle\lf              56,900      29.5     1.5
          231C-Southern Cumberland Plateau\lf          8,700       4.5     0.2
          231D-Southern Ridge and Valley\lf            6,700       3.5     0.2
          231E-Mid Coastal Plains, Western\lf         37,700      19.5     1.0
          231F-Eastern Gulf Prairies and Marshes\lf    2,200       1.2     0.1
          231G-Arkansas Valley\lf                      7,600       3.9     0.2

232\lf    \lf                                        173,800               4.8
          232A-Middle Atlantic Coastal Plain\lf       17,800      10.2     0.5
          232B-Coastal Plains and Flatwoods, Lower\lf          86,800      50.0     2.4
          232C-Atlantic Coastal Flatlands\lf          23,300      13.4     0.6
          232D-Florida Coastal Lowlands (Western)\lf  12,900       7.4     0.4
          232E-Louisiana Coast Prairies and Marshes\lf         13,700       7.9     0.4
          232F-Coastal Plains and Flatwoods, Western Gulf\lf   13,000       7.5     0.3
          232G-Florida Coastal Lowlands (Eastern)\lf   6,300       3.6     0.2
                                                                         
234\lf    234A-Mississippi Alluvial Basin\lf          44,300               1.2

M231\lf   M231A-Ouachita Mountains\lf                  8,800               0.2

242\lf    242A-Willamette Valley and Puget Trough\lf  14,900               0.4

M242\lf   \lf                                         53,400               1.5
          M242A-Oregon and Washington Coast Ranges\lf          15,700      29.4     0.5
          M242B-Western Cascades\lf                   15,400      28.8     0.4
          M242C-Eastern Cascades\lf                   22,300      41.8     0.6

M244\lf   \lf                                         40,000               1.1
          M244A-Chugach-St. Elias Mountains\lf        27,000      67.5     0.7
          M244B-Lynn Canal\lf                          5,900      14.7     0.2
          M244C-Boundary Range\lf                      7,100      17.8     0.2

M245\lf   \lf                                         23,900               0.7
          M245A-Northern Gulf\lf                       7,400      30.9     0.2
          M245B-Northern Alexander Archipelago\lf      5,800      24.3     0.2
          M245C-Southern Alexander Archipelago\lf     10,700      44.8     0.3
\hrule
                                                               Extent   Extent
                                                                 in       in  
Province  Section                                     Area    Province   U.S.
\hrule
                                                       mi2        %        %  

251\lf    \lf                                        218,200               6.1
          251A-Red River Valley\lf                    18,300       8.4     0.5
          251B-North-Central Glaciated Plains\lf      51,400      23.6     1.4
          251C-Central Dissected Till Plains\lf       67,900      31.1     1.9
          251D-Central Till Plains\lf                 36,100      16.5     1.0
          251E-Osage Plains\lf                        18,100       8.3     0.5
          251F-Flint Hills\lf                         17,000       7.8     0.5
          251G-Central Loess Plains\lf                 9,400       4.3     0.3

255\lf    \lf                                         80,100               2.2
          255A-Cross Timbers and Prairie\lf           35,900      44.8     1.0
          255B-Blackland Prairies\lf                  13,200      16.5     0.4
          255C-Oak Woods and Prairies\lf              21,900      27.3     0.6
          255D-Central Gulf Prairies and Marshes\lf    9,100      11.4     0.2

261\lf    \lf                                         10,300               0.3
          261A-Central California Coast\lf             5,500      53.4     0.2
          261B-Southern California Coast\lf            4,800      46.6     0.1

262\lf    262A-Great Valley\lf                        19,200               0.5

263\lf    263A-Northern California Coast\lf            4,600               0.1

M261\lf   \lf                                         68,300               1.9
          M261A-Klamath Mountains\lf                  16,100      23.6     0.4
          M261B-Northern California Coast Ranges\lf    6,300       9.2     0.2
          M261C-Northern California Interior Coast Ranges\lf    2,700       4.0     0.1
          M261D-Southern Cascades\lf                   6,300       9.2     0.2
          M261E-Sierra Nevada\lf                      18,200      26.6     0.5
          M261F-Sierra Nevada Foothills\lf             8,900      13.0     0.2
          M261G-Modoc Plateau\lf                       9,800      14.4     0.3

M262\lf   \lf                                         24,900               0.7
          M262A-Central California Coast Ranges\lf    12,400      49.8     0.3
          M262B-Southern California Mountains and Valleys\lf   12 500      50.2     0.4

311\lf    311A-Redbed Plains\lf                       17,600               0.5

313\lf    \lf                                         75,300               2.1
          313A-Grand Canyon\lf                        22,900      30.4     0.6
          313B-Navajo Canyonlands\lf                  21,900      29.1     0.6
          313C-Tonto Transition\lf                    17,400      23.1     0.5
          313D-Painted Desert\lf                       9,600      12.8     0.3
          313E-Central Rio Grande Intermontane\lf      3,500       4.6     0.1

\hrule
                                                               Extent   Extent
                                                                 in       in  
Province  Section                                     Area    Province   U.S.
\hrule
                                                       mi2        %        %  

315\lf    \lf                                        160,900               4.5
          315A-Pecos Valley\lf                        19,400      12.0     0.5
          315B-Texas High Plains\lf                   48,400      30.1     1.4
          315C-Rolling Plains\lf                      38,800      24.1     1.1
          315D-Edwards Plateau\lf                     21,900      13.6     0.6
          315E-Rio Grande Plain\lf                    29,700      18.5     0.8
          315F-Southern Gulf Prairies and Marshes\lf   2,700       1.7     0.1

M313\lf   \lf                                         50,200               1.4
          M313A-White Mountain-San Francisco Peaks-Mogollon                     
            Rim\lf                                    35,100      69.9     1.0
          M313B-Sacramento-Manzano Mountain\lf        15,100      30.1     0.4

321\lf    \lf                                         85,200               2.4
          321A-Basin and Range\lf                     72,900      85.6     2.0
          321B-Stockton Plateau\lf                    12,300      14.4     0.4

322\lf    \lf                                         87,700               2.4
          322A-Mojave Desert\lf                       44,200      50.4     1.2
          322B-Sonoran Desert\lf                      38,700      44.1     1.1
          322C-Colorado Desert\lf                      4,800       5.5     0.1

331\lf    \lf                                        290,700               8.1
          331A-Palouse Prairie\lf                      6,600       2.3     0.2
          331B-Southern High Plains\lf                17,000       5.8     0.5
          331C-Central High Tablelands\lf             25,700       8.8     0.7
          331D-Northwestern Glaciated Plains\lf       40,700      14.0     1.1
          331E-Northern Glaciated Plains\lf           26,900       9.3     0.7
          331F-Northwestern Great Plains\lf           76,100      26.2     2.1
          331G-Powder River Basin\lf                  45,000      15.5     1.3
          331H-Central High Plains\lf                 23,300       8.0     0.6
          331I-Arkansas Tablelands\lf                 23,400       8.0     0.7
          331J-Northern Rio Grande Basin\lf            6,000       2.1     0.2

332\lf    \lf                                        134,000               3.7
          332A-Northeastern Glaciated Plains\lf       27,900      20.8     0.8
          332B-Western Glaciated Plains\lf            11,600       8.6     0.3
          332C-Nebraska Sand Hills\lf                 18,700      14.0     0.5
          332D-North-Central Great Plains\lf          16,700      12.5     0.5
          332E-South-Central Great Plains\lf          59,100      44.1     1.6

M331\lf   \lf                                        102,300               2.8
          M331A-Yellowstone Highlands\lf              13,400      13.1     0.4
          M331B-Bighorn Mountains\lf                   5,200       5.1     0.1
          M331D-Overthrust Mountains\lf               17,900      17.5     0.5
          M331E-Uinta Mountains\lf                     7,400       7.2     0.2
          M331F-Southern Parks and Rocky Mountain Ranges\lf     7,400       7.2     0.2
          M331G-South-Central Highlands\lf            17,900      17.5     0.5
          M331H-North-Central Highlands and Rocky Mountain\lf  12,100      11.8     0.3
          M331I-Northern Parks and Ranges\lf          18,000      17.6     0.5
          M331J-Wind River Mountain\lf                 3,000       3.0     0.1
\hrule
                                                               Extent   Extent
                                                                 in       in  
Province  Section                                     Area    Province   U.S.
\hrule
                                                       mi2        %        %  

M332\lf   \lf                                         81,800               2.3
          M332A-Idaho Batholith\lf                    16,800      20.5     0.5
          M332B-Bitterroot Valley\lf                   7,500       9.2     0.2
          M332C-Rocky Mountain Front\lf                2,700       3.3     0.1
          M332D-Belt Mountains\lf                     12,200      14.9     0.3
          M332E-Beaverhead Mountains\lf               19,600      24.0     0.5
          M332F-Challis Volcanics\lf                   5,600       6.8     0.2
          M332G-Blue Mountains\lf                     17,400      21.3     0.5

M333\lf   \lf                                         38,100               1.1
          M333A-Okanogan Highlands\lf                 13,000      34.1     0.4
          M333B-Flathead Valley\lf                     8,200      21.5     0.2
          M333C-Northern Rockies\lf                    4,100      10.8     0.1
          M333D-Bitterroot Mountains\lf               12,800      33.6     0.4

M334\lf   M334A-Black Hills\lf                         3,700               0.1

341\lf    \lf                                        107,100               3.0
          341A-Bonneville Basin\lf                    25,600      23.9     0.7
          341B-Northern Canyon Lands\lf               15,200      14.2     0.4
          341C-Uinta Basin\lf                          3,500       3.3     0.1
          341D-Mono\lf                                10,000       9.3     0.3
          341E-Lahontan Basin\lf                      25,500      23.8     0.7
          341F-Southeastern Great Basin\lf            14,600      13.6     0.4
          341G-Northeastern Great Basin\lf            12,700      11.9     0.4

342\lf    \lf                                        159,100               4.4
          342A-Bighorn Basin\lf                        7,600       4.8     0.2
          342B-Northwestern Basin and Range\lf        44,500      28.0     1.2
          342C-Owyhee Uplands\lf                      28,700      18.0     0.8
          342D-Snake River Basalts\lf                 10,300       6.5     0.3
          342E-Bear Lake\lf                            3,100       1.9     0.1
          342F-Central Basin and Hills\lf             15,700       9.9     0.4
          342G-Green River Basin\lf                   19,600      12.3     0.6
          342H-High Lava Plains\lf                     8,200       5.1     0.2
          342I-Columbia Basin\lf                      21,400      13.5     0.6

M341\lf   \lf                                         43,600               1.2
          M341A-Central Great Basin Mountains\lf      24,400      56.0     0.7
          M341B-Tavaputs Plateau\lf                    7,000      16.0     0.2
          M341C-Utah High Plateaus and Mountains\lf   12,200      28.0     0.3

411\lf    411A-Everglades\lf                           7,800               0.2

M411\lf   M411A-Dry-Humid Mountains\lf                 3,700               0.1

M423\lf   M423A-Hawaiian Islands\lf                    6,500               0.2
\hrule
          TOTAL                                               3,592,800

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