| Public Employees for Environmental ResponsibilityEIN 93-1102740 | Environment | MD | $829,164Small | 91.26 |
| Pure EarthEIN 13-4075779 | Environment | NY | $4,713,887Mid-sized | 97.74 |
| Quebec-Labrador FoundationEIN 13-6155399 | Environment | MA | $1,895,344Small | 92.79 |
| Rails-To-Trails ConservancyEIN 52-1437006 | Environment | DC | $9,232,373Mid-sized | 90.68 |
| Rainforest Action NetworkEIN 94-3045180 | Environment | CA | $6,840,501Mid-sized | 89.83 |
| Rainforest AllianceEIN 13-3377893 | Environment | NY | $39,968,460Large | 79.81 |
| Rainforest Foundation USEIN 95-1622945 | Environment | NY | $2,617,359Small | 98.23 |
| Rainforest TrustEIN 13-3500609 | Environment | VA | $16,200,766Large | 94.69 |
| Randall's Island Park AllianceEIN 13-3787630 | Environment | NY | $7,982,600Mid-sized | 89.46 |
| RareEIN 23-7380563 | Environment | VA | $25,106,435Large | 92.29 |
| Regional Parks FoundationEIN 23-7011877 | Environment | CA | $1,649,524Small | 90.50 |
| Regional Trail CorporationEIN 25-1660116 | Environment | PA | $874,198Small | 83.96 |
| Resource CentralEIN 84-0808982 | Environment | CO | $2,340,605Small | 92.51 |
| Resources for the FutureEIN 53-0220900 | Environment | DC | $13,755,089Large | 89.69 |
| River NetworkEIN 93-0969979 | Environment | CO | $2,276,677Small | 88.96 |
| Riveredge Nature CenterEIN 39-6108549 | Environment | WI | $1,881,013Small | 91.18 |
| Riverfront RecaptureEIN 06-1045653 | Environment | CT | $3,088,203Small | 92.56 |
| RiverkeeperEIN 13-3204621 | Environment | NY | $4,274,476Mid-sized | 93.25 |
| RiverlifeEIN 31-1674160 | Environment | PA | $2,120,404Small | 85.03 |
| Riverside Park ConservancyEIN 13-3443825 | Environment | NY | $4,726,703Mid-sized | 88.60 |
| Rocky Mountain ConservancyEIN 84-0472090 | Environment | CO | $3,017,070Small | 96.63 |
| Rocky Mountain InstituteEIN 74-2244146 | Environment | CO | $33,402,821Large | 94.57 |
| Rose Foundation for Communities and the EnvironmentEIN 94-3179772 | Environment | CA | $7,448,602Mid-sized | 100.00 |
| Rural Advancement Foundation International-USAEIN 56-1704863 | Environment | NC | $2,116,129Small | 100.00 |
| San Antonio Botanical Garden SocietyEIN 74-2178792 | Environment | TX | $2,825,220Small | 88.42 |
| San Diego Botanic GardenEIN 95-6120581 | Environment | CA | $2,978,807Small | 84.42 |
| San Diego CoastkeeperEIN 33-0647946 | Environment | CA | $668,734Small | 78.81 |
| San Diego River Park FoundationEIN 01-0565671 | Environment | CA | $939,333Small | 85.40 |
| San Francisco BaykeeperEIN 68-0120240 | Environment | CA | $1,512,332Small | 84.75 |
| San Francisco Botanical Garden SocietyEIN 94-6050168 | Environment | CA | $4,261,791Mid-sized | 92.52 |
| San Francisco Parks AllianceEIN 23-7131784 | Environment | CA | $15,142,255Large | 92.48 |
| San Joaquin River Parkway and Conservation TrustEIN 77-0196692 | Environment | CA | $1,749,897Small | 90.56 |
| Sanibel-Captiva Conservation FoundationEIN 59-1205087 | Environment | FL | $3,095,476Small | 90.45 |
| Santa Barbara Botanic GardenEIN 95-1644628 | Environment | CA | $3,907,707Mid-sized | 90.80 |
| Schlitz Audubon Nature CenterEIN 39-1231819 | Environment | WI | $2,897,570Small | 90.69 |
| Seattle Audubon SocietyEIN 91-6009716 | Environment | WA | $1,068,105Small | 86.75 |
| Seattle Parks FoundationEIN 91-1998597 | Environment | WA | $2,525,864Small | 97.13 |
| Second NatureEIN 04-3195772 | Environment | MA | $1,691,248Small | 89.82 |
| Seed Savers ExchangeEIN 43-1214133 | Environment | IA | $5,385,772Mid-sized | 84.73 |
| Shelburne FarmsEIN 03-0229347 | Environment | VT | $5,255,194Mid-sized | 91.56 |
| Sierra Club FoundationEIN 94-6069890 | Environment | CA | $72,890,348Large | 95.21 |
| Sierra Nevada AllianceEIN 77-0343881 | Environment | CA | $825,345Small | 79.38 |
| Sky Island AllianceEIN 86-0796748 | Environment | AZ | $1,171,111Small | 97.70 |
| Society for the Protection of New Hampshire ForestsEIN 02-0222237 | Environment | NH | $7,278,002Mid-sized | 94.94 |
| Solar Cookers InternationalEIN 68-0153141 | Environment | CA | $773,030Small | 91.37 |
| SOLVEEIN 93-0579286 | Environment | OR | $1,209,987Small | 78.43 |
| Sonoran InstituteEIN 86-0684610 | Environment | AZ | $2,969,310Small | 82.94 |
| SoundWatersEIN 06-1263947 | Environment | CT | $2,007,465Small | 94.48 |
| Southeast Alaska Conservation CouncilEIN 92-0062992 | Environment | AK | $589,607Small | 82.59 |
| Southern Environmental Law CenterEIN 52-1436778 | Environment | VA | $26,551,471Large | 100.00 |
| Southern Utah Wilderness AllianceEIN 94-2936961 | Environment | UT | $2,658,079Small | 93.68 |
| Stand.earthEIN 94-3331587 | Environment | CA | $3,081,289Small | 88.89 |
| Stony Brook Millstone Watershed Association EIN 21-0649717 | Environment | NJ | $2,183,497Small | 91.01 |
| Stroud Water Research CenterEIN 52-2081073 | Environment | PA | $9,504,082Mid-sized | 91.98 |
| Student Conservation Association EIN 91-0880684 | Environment | VA | $43,289,688Large | 89.65 |
| Sustainable ConservationEIN 94-3232437 | Environment | CA | $5,612,199Mid-sized | 88.59 |
| Sustainable NorthwestEIN 93-1152222 | Environment | OR | $1,715,550Small | 79.08 |
| Teton Science SchoolsEIN 83-0219163 | Environment | WY | $14,782,834Large | 90.70 |
| Texas Parks and Wildlife FoundationEIN 74-2602504 | Environment | TX | $6,241,257Mid-sized | 95.05 |
| The Adirondack CouncilEIN 14-1594386 | Environment | NY | $1,901,232Small | 97.45 |