1850 Atlas
| Name | What | Place | Pop | Other |
| Cicero | PT | Onondaga Co, NY | 2,980 | water by Oneida lake & Chittenango creek |
| Cicero | PT | Hamilton Co, IN | ||
| Cincinnati | PV | Ralls Co, MO | water by Salt river | |
| Cincinnati | PO | Appanoose Co, IA | ||
| Cincinnati | PO | Walker Co, TX | ||
| Cincinnati | City | Hamilton Co, OH | 115,436 | water by Ohio river |
| Cincinnatus | PT | Cortland Co, NY | 1,206 | water by Ostelic creek |
| Cinnaminson | PO | Burlington Co, NJ | ||
| Circleville | PO | Tazwell Co, IL | ||
| Circleville | PT, CH | Pickaway Co, OH | 3,411 | seat of justice, water by Scioto river & Ohio canal |
| Circleville | PO | Loudoun Co, VA | ||
| Citico | PO | Monroe Co, TN | ||
| City | PO | Amenia twp, Dutchess Co, NY | ||
| City Point | PV | Prince George Co, VA | water by James & Appomattox rivers | |
| City Point | PO | Itawamba Co, MS | ||
| City West | V | Porter Co, IN | water by Lake Michigan | |
| Claiborne | PV | Monroe Co, AL | water by Alabama river | |
| Claiborne | T | Union Co, OH | 919 | |
| Clairnoreville | PV | Yazoo Co, MS | ||
| Clairville | PO | Winnebago Co, WI | ||
| Clapps | PO | Guilford Co, NC | ||
| Clappville | PV | Leicester twp, Worcester Co, MA | water by tributaries of Quinebaug river | |
| Clara | PT | Potter Co, PA | 89 | |
| Claremont | PT | Sullivan Co, NH | 3,606 | water by Connecticut & Sugar rivers |
| Claremont | PV | Pickens dist, SC | ||
| Clarence | PT | Erie Co, NY | 2,727 | water by Ransom's & Tonawanda creeks |
| Clarence | PO | Calhoun Co, MI | ||
| Clarence Centre | PO | Erie Co, NY | ||
| Clarendon | PT | Rutland Co, VT | 1,477 | water by Otter creek |
| Clarendon | PT | Orleans Co, NY | 1,809 | water by Oak Orchard & Sandy creeks |
| Clarendon | PT | Calhoun Co, MI | 669 | |
| Clarendon | PO | Monroe Co, AR | ||
| Clarendon Springs | PO | Clarendon twp, Rutland Co, VT | ||
| Clarendon | PO | Sumter dist, SC | ||
| Claridon | PO | Geauga Co, OH | water by tributaries of Cuyaboga river | |
| Claridon | T | Marion Co, OH | ||
| Clark | PO | Mercer Co, PA | ||
| Clark | T | Lincoln Co, MO | ||
| Clark | T | Chariton Co, MO | 720 | |
| Clark | T | Gasconade Co, MO | ||
| Clark | T | Johnson Co, AR | 574 | |
| Clark | T | Pope Co, AR | ||
| Clark | T | Brown Co, OH | 1,281 | |
| Clark | T | Clinton Co, OH | 1,654 | |
| Clark | T | Montgomery Co, IN | 1,301 | |
| Clarks | PT | Coshocton Co, OH | 833 | |
| Clarksborough | PV | Greenwich twp, Gloucester Co, NJ | ||
| Clarksburgh | PO | Erie Co, NY | ||
| Clarksburgh | PV | Upper Freehold twp, Monmouth Co, NJ | ||
| Clarksburgh | PV | Montgomery Co, MD | ||
| Clarksburgh | PV, CH | Lewis Co, KY | seat of justice, water by Salt Lick creek | |
| Clarksburgh | PV | Deerfield twp, Ross Co, OH | ||
| Clarksburgh | V | Decatur Co, IN | ||
| Clarksburgh | T | Berkshire Co, MA | 386 | water by branch of Hoosack river |
| Clarksburgh | PO | Indiana Co, PA | ||
| Clarksburgh | PT, CH | Harrison Co, VA | seat of justice | |
| Clark's Corner | PO | Ashtabula Co, OH | ||
| Clark's Factory | PO | Delaware Co, NY | ||
| Clarksfield | PT | Huron Co, OH | 1,454 | water by Vermilion river |
| Clark's Fork | PO | York dist, SC | ||
| Clark's Fork | PO | Copper Co, MO | ||
| Clark's Green | PO | Luzerne Co, PA | ||
| Clark's Mills | PO | Moore Co, NC | ||
| Clark's Mills | PO | Washington Co, VA | ||
| Clark's Mills | PO | Hempstead Co, AR | ||
| Clark's River | PO | Callaway Co, KY | ||
| Clarkson | PT | Monroe Co, NY | 4,555 | water by Little Salmon & Sandy creeks |
| Clarkson Centre | PO | Clarkson twp, Monroe Co, NY | ||
| Clarkson | PV | Middleton twp, Columbiana Co, OH | ||
| Clarkston | PO | Oakland Co, MI | ||
| Clarkstown | PT | Rockland Co, NY | 3,111 | seat of justice, water by Hudson river & Rockland lake |
| Clarksville | PV, CH | Clarke Co, AL | seat of justice | |
| Clarksville | PO | New Scotland twp, Albany Co, NY | ||
| Clarksville | T | Coos Co, NH | 187 | water by Connecticut river |
| Clarksville | PV | Lebanon twp, Hunterdon Co, NJ | water by Spruce run | |
| Clarksville | T | Alleghany Co, NY | 608 | |
| Clarksville | PO | Anne Arundel Co, MD | ||
| Clarksville | PV | Greene Co, PA | water by Ten Mile Creek | |
| Clarksville | PV | Mecklenburgh Co, VA | ||
| Clarksville | PV | Habersham Co, GA | seat of justice | |
| Clarksville | PV, CH | Montgomery Co, TN | seat of justice, water by Red & Cumberland rivers | |
| Clarksville | PV | Vernon twp, Clinton Co, OH | ||
| Clarksville | PV | Pike Co, MO | water by Mississippi river | |
| Clarksville | PV, CH | Johnson Co, AR | seat of justice | |
| Clarksville | PO | Spartanburgh dist, SC | ||
| Clarksville | PO | Red River Co, TX | ||
| Clarksville | PO | Hamilton Co, IN | ||
| Claryville | PO | Sullivan Co, NY | ||
| Clauselville | PO | Monroe Co, AL | ||
| Claussville | PO | Lehigh Co, PA | ||
| Claveback | PT | Columbia Co, NY | 3,208 | water by Claverack creek |
| Clay | PT | Onondaga Co, NY | 3,402 | water by Oneida, Senecca & Oswego rivers |
| Clay | T | Lafayette Co, MO | 1,716 | |
| Clay | T | Ralls Co, MO | ||
| Clay | T | Tuscarawas Co, OH | 1,270 | water by Muskingum river & Ohio canal |
| Clay | T | Scioto Co, OH | 882 | water by Scioto river |
| Clay | T | Ottawa Co, OH | water by Portage | |
| Clay | T | Montgomery Co, OH | 1,905 | |
| Clay | T | Highland Co, OH | 1,108 | |
| Clay | T | Hamilton Co, IN | 1,107 | |
| Clay | T | Allen Co, OH | ||
| Clay | T | Gallia Co, OH | 949 | |
| Clay | T | Knox Co, OH | 1,140 | |
| Clay | T | La Grange Co, IN | 464 | |
| Clay | T | Owen Co, IN | ||
| Clay | T | Wayne Co, IN | 769 | |
| Clay | PO | Dunklin Co, IL | 510 | |
| Clay | PO | Yancey Co, NC | ||
| Clay Hill | PO | Marengo Co, AL | ||
| Clay Hill | PO | York dist, SC | ||
| Claypool | PO | Kosclusko Co, IN | ||
| Clay's Point | PO | Lewis Co, VA | ||
| Claysville | PV | Westland twp, Guernsey Co, OH | ||
| Claysville | PV | Washington Co, PA | 275 | |
| Claysville | PV | Marshall Co, AL | ||
| Claysville | PV | Harrison Co, KY | ||
| Claysville | PV | Washington Co, IN | ||
| Claysville | PO | Wood Co, VA | ||
| Claysville | PO | Boone Co, MO | ||
| Clayton | PT | Jefferson Co, NY | 4,195 | water by St Lawrence & Chaumont river & French creek |
| Clayton | PO | Montgomery Co, OH | ||
| Clayton | PV, CH | Rabun Co, GA | seat of justice | |
| Clayton | PV, CH | Barbour Co, AL | seat of justice | |
| Clayton | PV | Adams Co, IL | 781 | |
| Clayton | T | Perry Co, OH | 1,594 | |
| Clayton | PO | Berks Co, PA | ||
| Clayton | PO | Lenawee Co, MI | ||
| Clayton | PO | Clayton Co, IA | ||
| Claytona | PO | Morgan Co, OH | ||
| Clayton's Mills | PO | Pickens dist, SC | ||
| Claytonville | PV, CH | Henderson Co, NC | seat of justice, water by French Broad river | |
| Clay Village | PV | Shelby Co, KY | ||
| Clayville | PO | Oneida Co, NY | ||
| Clayville | PO | Providence Co, RI | ||