| Surnames | Time Period | Researcher |
| Caffrey | 1800 - 1920 | Brian Joseph Caffrey |
| Caldwell | 1845 - 1928 | N. Boland |
| Caldwell | . | Susie Chabak |
| Calhoun | 1940 - present | Gene Adrian Calhoun, Jr. |
| Calvert | . | Sue Marchant |
| Camp | 1870 - 1920's | Judy Dombrowski |
| Camp | 1875 - 1910 | Marjorie Thompson |
| Canton | 1860 - 1880 | Lin Meeker |
| Cardell | 1900s | Grant |
| Carleton | 1860 - 1908 | Kathryn Andres |
| Carlin | 1900 - 1912 | Frankie (Carlin) Meyer |
| Carmichael | 1880 - now | Sharon Robey Bambara |
| Carnahan | 1880 - 1960's | Tim L. Carnahan |
| Carnahan | 1880 - 1960 | Ruth McDaniel |
| Carpenter | 1860 - 1920 | Wilma Sinnott |
| Carriker | . | Jenell Rector Cremeans |
| Carroll | . | Larry D. Brooks |
| Carroll | 1904 - 1936 | Rene Worland |
| Carson | 1900 - 1999 | Ike Stanley |
| Carter | 1880 - now | D.A. Blakemore |
| Casteel | 1890 - now | Shirley Ortiz |
| Ceurvorst | 1880 - now | Gerard Ceurvorst |
| Chancel | 1890 - 1920 | Frankie (Carlin) Meyer |
| Chandler | 1910 - 1920 | Lavena Crawford |
| Chaney | 1850 - 1940 | Darla C. Clark Knytych |
| Chapman | 1880 - 1900 | Claudette |
| Chowning | 1900 - 1905 | Janis E. Freeman |
| Church | 1870 - now | Teresa Church |
| Church | 1930 - 1945 | Joan Thomas |
| Clark | 1850 - now | Shawna Clark |
| Clasen | 1870's - 1900 | Michael Hamersky |
| Clayton | . | Hope Brush |
| Clingingsmith | 1941 - 1965 | Lenora Marsh |
| Clinton | 1890 | Bill & Teresa McCormick |
| Cobb | 1895 - c1910 | Lova Fincham Kraft |
| Coble | 1870 - 1950 | Deb Shillo |
| Cochran | 1837 - 1935 | Walter Thomas E. Cochran |
| Cole | 1880 - 1916 | Constance Cole |
| Coleman | 1880 - 1970 | Pat Burke |
| Colley | 1870 - 1890 | June |
| Collins | . | Richard Collins |
| Collyer | 1960's | Grady B. Ireland |
| Conely | 1898 - 1901 | Cynthia Isley |
| Connell | 1900 - 1955 | Tonya |
| Conner | 1960 - now | Christopher Lynn Braddy Conner |
| Cook | 1800 - now | Craig Cook |
| Cooley | 1875 - now | Stephen Carlile |
| Cooper | 1902 - 1945 | Linda Debarea |
| Cordel | 1870's - now | Michael Hamersky |
| Corn | 1860 - 1920 | Betty M. Bronstad |
| Cornell | 1995 - now | Melissa Coleman Cornell |
| Corr | 1890 - now | JoAnnn Preator |
| Cotten | 1950 | Joan Hooper (Cotten) |
| Coulson | 1907 - now | Leif Geilman |
| Courtney | 1900 - 1960 | Thomas Currey |
| Cousatte | 1930 | Kathy Sisk |
| Covault | 1893 - now | Allen W. Davis |
| Cowan | . | Vickey-Arlene Collins |
| Cowden | 1890's - now | Lisa Hale |
| Cox | 1860 - now | Patricia H. Smith |
| Cozine | 1908 - 1976 | Tommy Holland |
| Crandell | 1920 - now | Helen Wilson |
| Crawford | 1870 - 1920's | Judy Dombrowski |
| Crawford | 1875 - 1910 | Marjorie Thompson |
| Crawford | Julie Willie | |
| Criger | Melody Criger | |
| Crum | 1860 - now | Gail J. Crum Henderson-Wishnefsky |
| Crum | . | Tom Crum |
| Cuhningham | 1895 - 1945 | Darleen |
| d'Albenas | 1860 - 1910 | Timothy d'Albenas |
| Daisy | . | Michael & Kathleen Daisy |
| Daisy | 1872 - now | Dennis Daisy |
| Dale | 1870 - 1930 | Jan LaMotte |
| Dameron | c1937 | Catherine Pogan |
| Daniel | 1870 - 1950 | Robert Black |
| Danley | 1880's | Jennifer Beatty |
| Davidson | 1875 - now | Stephen Carlile |
| Davidson | 1960 - 1986 | Chuck Davidson |
| Davis | 1943 - 1944 | Hope Brush |
| Davis | 1883 - 1910 | Frances Ostermann |
| Davison | 1910 - 1930 | Patricia Reynolds Oeser |
| Dawson | 1880-1930s | Laverne Galeener-Moore |
| Day | 1920 - now | Sandra Jones |
| Deal | 1860 - 1920 | Robert Black |
| Deaton | 1907 - 1917 | Elizabeth |
| Deeter | 1880 - now | Marvin Deeter |
| Demming | 1800 - 1920 | Brian Joseph Caffrey |
| DeShazer | Linda London | |
| DeVaughn | 1920 | Lydia DeVaughn |
| Dewing | . | Kim M. Estes |
| Dickens | . | Kathleen Dickens |
| Diehl | 1860 - 1920 | Robert Black |
| Dildine | 1880 - 1895 | Verne Ross Clark |
| Disbrow | 1870 - now | Cheryl Disbrow Kinsel |
| Ditgen | late 1900's | Anisah Haynes |
| Dobbin | 1880 - | Glenda Nighswonger |
| Dodd | 1880 - now | Donna Yates |
| Dold | 1870's - now | Michael Hamersky |
| Dom | 1925 - now | Byron Dom |
| Donley | 1880's | Jennifer Beatty |
| Donnelly | 1880's | Jennifer Beatty |
| Dorey | 1900 - 1964 | Stephanie Suela |
| Dorrance | 1930 - now | Kaye Mushalik |
| Dorsey | 1890’s - now | Michael A. Campa |
| Downing | 1890 - 1940 | Ray Downing |
| Doyle | 1930's | George Robert McCormick |
| Drollinger | . | Gordon L. Drollinger |
| Duffner | 1890 - 1980 | JoAnn Preator |
| Dunlap | 1860 - 1880 | Lin Meeker |
| Dunn | . | Mary Grabanski |
| Durley | 1860 - 1900 | Maryalice Herrick Quinn |
| Duschek/Dusek | 1877 | Frances Spagnoletti |
| Dvorak | 1880 - now | Susan Hatfield |
| Dwyer | 1890 - 1910 | Trudy Moore |
| Dye | 1980 - 1986 | DaRyta Moss |
| Dyer | Veanna Carr |