| COSI Center of Science and IndustryEIN 31-4383802 | Arts, Culture, Humanities | OH | $17,916,053Large | 85.79 |
| Coulee Region Humane SocietyEIN 23-7366713 | Animals | WI | $1,192,417Small | 91.24 |
| Council for a Strong AmericaEIN 13-3840271 | Research and Public Policy | DC | $11,660,559Mid-sized | 95.16 |
| Council for Children's RightsEIN 56-1325184 | Human Services | NC | $2,443,075Small | 81.60 |
| Council for Economic EducationEIN 13-1623848 | Education | NY | $5,186,704Mid-sized | 77.37 |
| Council for Educational ChangeEIN 01-0638224 | Education | FL | $2,174,131Small | 85.92 |
| Council for National PolicyEIN 72-0921017 | Research and Public Policy | DC | $2,680,790Small | 84.02 |
| Council of Independent CollegesEIN 01-6004776 | Education | DC | $13,706,554Large | 87.42 |
| Council of Social ConcernEIN 04-2494773 | Human Services | MA | $2,065,231Small | 79.59 |
| Council on Foreign RelationsEIN 13-1628168 | International | NY | $69,262,800Large | 87.81 |
| Country Music FoundationEIN 62-0753887 | Arts, Culture, Humanities | TN | $31,719,231Large | 80.61 |
| Couple to Couple LeagueEIN 31-0842914 | Human and Civil Rights | OH | $1,615,421Small | 86.15 |
| Courage WorldwideEIN 20-3126288 | International | CA | $991,803Small | 76.16 |
| Court Appointed Special Advocates of Collin CountyEIN 75-2391961 | Human Services | TX | $1,201,787Small | 91.33 |
| Court Appointed Special Advocates of Orange CountyEIN 33-0069334 | Human Services | CA | $2,514,265Small | 87.81 |
| Covenant House AlaskaEIN 13-3419755 | Human Services | AK | $7,874,566Mid-sized | 93.90 |
| Covenant House CaliforniaEIN 13-3391210 | Human Services | CA | $10,013,415Mid-sized | 95.24 |
| Covenant House FloridaEIN 59-2323607 | Human Services | FL | $8,311,668Mid-sized | 91.57 |
| Covenant House MichiganEIN 38-3351777 | Human Services | MI | $4,689,658Mid-sized | 96.08 |
| Covenant House MissouriEIN 43-1821599 | Human Services | MO | $3,540,058Mid-sized | 89.95 |
| Covenant House New JerseyEIN 13-3537710 | Human Services | NJ | $10,736,994Mid-sized | 91.77 |
| Covenant House New OrleansEIN 58-1669937 | Human Services | LA | $5,601,620Mid-sized | 97.82 |
| Covenant House New YorkEIN 13-3076376 | Human Services | NY | $21,165,223Large | 88.04 |
| Covenant House TexasEIN 76-0050882 | Human Services | TX | $5,541,296Mid-sized | 90.58 |
| Covenant House WashingtonEIN 13-3537709 | Human Services | DC | $5,553,135Mid-sized | 90.93 |
| Coyote Hill Christian Children's HomeEIN 43-1601128 | Human Services | MO | $1,387,328Small | 83.99 |
| Cradle BeachEIN 16-0743025 | Human Services | NY | $2,496,471Small | 83.94 |
| Cradles to CrayonsEIN 04-3584367 | Human Services | MA | $15,682,610Large | 96.46 |
| Crayons to ClassroomsEIN 26-1594574 | Education | OH | $3,471,859Small | 97.17 |
| Crayons to ComputersEIN 31-1507076 | Education | OH | $10,934,616Mid-sized | 92.38 |
| CREATE FoundationEIN 23-7248582 | Community Development | MS | $8,181,939Mid-sized | 90.58 |
| Creative ActionEIN 74-2856925 | Human Services | TX | $3,712,943Mid-sized | 88.65 |
| Creative Capital FoundationEIN 31-1605982 | Arts, Culture, Humanities | NY | $5,792,226Mid-sized | 92.38 |
| Creative CommonsEIN 04-3585301 | Research and Public Policy | CA | $3,342,546Small | 89.05 |
| Creative MinistriesEIN 23-2269420 | Religion | PA | $1,980,048Small | 61.78 |
| Creative TimeEIN 13-2835847 | Arts, Culture, Humanities | NY | $2,920,073Small | 86.13 |
| Creede Repertory TheatreEIN 84-0660026 | Arts, Culture, Humanities | CO | $1,623,226Small | 91.03 |
| Crescent ProjectEIN 35-1790297 | Religion | IN | $1,844,034Small | 71.39 |
| Crisis Aid InternationalEIN 30-0060905 | International | MO | $2,225,357Small | 97.05 |
| Crisis Assistance MinistryEIN 56-1416719 | Human Services | NC | $15,189,615Large | 89.39 |
| Crisis Control MinistryEIN 23-7348168 | Human Services | NC | $4,455,399Mid-sized | 89.39 |
| Crisis Pregnancy Center of TidewaterEIN 54-1267311 | Health | VA | $1,618,062Small | 67.86 |
| Crisis Pregnancy Centers of Greater PhoenixEIN 86-0536082 | Health | AZ | $1,682,802Small | 79.16 |
| CRISTA MinistriesEIN 91-6012289 | Religion | WA | $114,902,453Large | 92.22 |
| Crohn's & Colitis Foundation EIN 13-6193105 | Health | NY | $75,664,404Large | 88.16 |
| Crooked Tree Arts CenterEIN 23-7187264 | Arts, Culture, Humanities | MI | $2,194,400Small | 82.56 |
| Cross Roads HouseEIN 22-2549963 | Human Services | NH | $1,740,795Small | 90.76 |
| Crossnore SchoolEIN 56-0567980 | Human Services | NC | $15,549,420Large | 94.62 |
| CrossOver Healthcare MinistryEIN 54-1371067 | Health | VA | $5,840,704Mid-sized | 89.02 |
| Crossroads CenterEIN 47-0700215 | Human Services | NE | $1,174,028Small | 65.07 |
| Crossroads Nogales MissionEIN 86-0804463 | Human Services | AZ | $920,167Small | 46.66 |
| Crossroads of MichiganEIN 38-2539852 | Human Services | MI | $1,325,518Small | 89.70 |
| Crossroads Prison MinistriesEIN 38-2540316 | Religion | MI | $1,852,405Small | 91.11 |
| Crossroads Urban CenterEIN 87-0295751 | Human Services | UT | $1,720,655Small | 94.78 |
| Crosstown Learning CenterEIN 73-0782748 | Human Services | OK | $2,339,373Small | 92.22 |
| Crosswinds Youth ServicesEIN 23-7376943 | Human Services | FL | $3,016,776Small | 87.25 |
| Crow Canyon Archaeological CenterEIN 84-0631786 | Arts, Culture, Humanities | CO | $4,488,765Mid-sized | 86.52 |
| Crown Financial MinistriesEIN 58-1260812 | Religion | TN | $4,923,465Mid-sized | 75.33 |
| Crown Point Community FoundationEIN 31-0247014 | Community Development | IN | $1,689,704Small | 83.83 |
| Crystal Peaks Youth RanchEIN 91-1821187 | Human Services | OR | $1,460,968Small | 70.49 |